A famous blockprint by Hokusai titled “Mount Fuji Seen from the Mountains of Totomi,” showing a crew of sawyers rip-sawing a timber into boards using maebiki ooga saws, one man on top and one underneath. Notice a third man to the left sitting under the timber sharpening another saw, perhaps his own or that of the fellow sitting in the background. A woman, probably the loving wife of the saw sharpener, has a baby wiggling around on her back trying to get a better view. She is no doubt waiting for her husband to pause his file work so she can deliver his lunch contained in the traditional furoshiki cloth depicted in her left hand. Some things never change with time or place, so she probably isn’t standing there silently, but I will leave the subject of the one-sided conversation to Gentle Reader’s imagination.
A society that puts equality—in the sense of equality of outcome—ahead of freedom will end up with neither equality nor freedom. The use of force to achieve equality will destroy freedom, and the force, introduced for good purposes, will end up in the hands of people who use it to promote their own interests.
Thomas Sowell
The name of this tool can be translated directly into English as “Front Pull Large Saw.” Kinda sorta almost hardly makes sense in light of the other tools that do the same job.
This tool is a large, relatively thick and heavy rip saw specialized for sawing logs into timbers and boards, but it can make various types of rip cuts in wood, sometimes pulled up through the kerf, and sometimes pulled down from below, as shown in the wood block print by Hokusai above.
Various timber and arborist’s crosscut saws have a gradually bent tang, while others have a cranked tang like the saw which is the subject of this article and shown in the photo above. Not seen in the photo is the tapered portion of the tang inside the stubby handle.
Although the scale may not be readily apparent from the photo, these handles are often quite large, perhaps 7~8cm in diameter and 15~20cm long, to provide a large bearing surface for two hands. This is definitively not a one-handed saw.
The best material for this type handle is said to be soft paulownia wood (桐) because it cushions the workman’s hands without becoming slippery when wet with perspiration, a common state for this hard-working tool.
There are four advantages to this saw of which your humble servant is aware. First, while it is by no means a lightweight wood-gobbler, it does not require the long, clumsy, heavy frame of two-man saws, so it can be more easily transported.
Two sawyers using a frame saw to rip planks. A heavy tool and surprisingly difficult to control.
Second, it can be operated by a single craftsman.
Third, due to its wider, much stiffer blade, the maebiki saw tends to cut a straighter kerf with less effort than two-man frame saws can typically achieve.
And finally, while the strip of metal forge-welded to the edge and containing all the teeth is hardened high-carbon tamahagane steel, the rest of the blade is comprised of unhardened low-carbon iron.
This bi-metal construction technique is not only ancient, it was once standard procedure among all civilizations back when steel was comparatively expensive (not really that long ago actually). As a result, the maebiki ooga saw employs far less costly steel than that required to make a two-man frame saw.
In any case, as Gentle Readers and Beloved Customers with experience ripping wide boards are no doubt aware, using human bones, muscles and tendons to saw boards and timbers requires patience, and a lot of sweaty, hard work. Thank heaven for machine saws.
I own two maebiki oga saws, both purchased at flea markets in Japan in the 1980’s before collecting them became popular. They are currently in storage in the USA, no doubt sad and lonely in the dark.
Long ago I had them both professionally evaluated and learned that they were produced of iron and tamahagane steel sometime during the mid-Edo Period (1603~1867).
I had them professionally sharpened and, just for the heck of it, used one to square up a pine timber under the tutelage of an old-timer. An interesting experience but one I would prefer to not repeat. For you see, while the saw was simply quivering with excitement at having sharp teeth again and tasting fresh wood after many many decades of neglect, I fear I did not provide it the excitement it so desperately wanted, disappointing it badly. At the time, I thought I heard a mumbling issuing from its many gullets, something about me being a lazy bum… But of course, that couldn’t have been the case (シ)
After that I mounted it over the door to my workshop so it could at least imbibe the savory smells of fresh sawdust on a regular basis as it gazed down upon its domain. No complaints so far.
Despite, or perhaps because of, its unusual appearance, no saw I am aware of exudes a more powerful presence, or contains more internal focused energy, than the maebiki ooga saw. What think ye?
If you have questions or would like to learn more about our tools, please click the “Pricelist” link here or at the top of the page and use the “Contact Us” form located immediately below.
Please share your insights and comments with everyone in the form located further below labeled “Leave a Reply.” We aren’t evil Google, fascist facebook, or thuggish Twitter and so won’t sell, share, or profitably “misplace” your information. If I lie may all my sawkerfs wander.
A clever person solves a problem. A wise person avoids it.”
Albert Einstein
We recently added a new product to our lineup of frightfully-sharp chisels called the “Hantatakinomi,” aka “Hanataki Chisels” which is the subject of this article.
Definition
Hantatakinomi means “Half-sized tatakinomi” and is pronounced Han/tah/tah/kee/no/mee.Traditionally popular in the Kansai area of Japan, this style of chisel never really caught on in the Tokyo area where your most humble and obedient servant is located, so developing a relationship with a reliable blacksmith willing to forge them to our specifications, and at a reasonable price, was an effort of several years.
Like all our tatakinomi, these Hantataki chisels have steel hoops and ferrules installed on tough Japanese oak handles, so as long as you are feeding them lots of yummy wood, they will simply wiggle with joy at being motivated by a heavy steel hammer from the break of day till the cows come home.
Product Development
Quality and performance are extremely important priorities to us at C&S Tools because we believe these qualities, combined with good customer service and a solid, pro-active warranty, are key to both customer satisfaction and wholesome guilt-free living. Don’t you agree?
After three years of meeting with blacksmiths, inspecting their forges, confirming their forging techniques and quality control methodology, having samples made, testing those samples to destruction, and repeatedly fine-tuning the design and specifications, we are at last ready to send our Hantataki chisels out into the world to find new masters, and much yummy wood.
That squeaking sound you may hear, BTW, is their joyous singing as they march forth; They love music, you know, even if they couldn’t carry a tune in a bucket.
If Gentle Reader wants to experience this heartfelt sound firsthand, try cutting a mortise with one of our Hanatataki chisels while humming The Heimatdamisch’s version of “Poker Face,” or The Ukulele Orchestra of Great Britain’s version of “Psycho Killer.” They especially seem to like music made by wooden instruments, you know.
Specifications
A comparison of the size of our 48mm Oiirenomi chisel (top), Hantataki Chisel (center), and Atsunomi chisel (bottom)
Our Hantataki chisels are of course hand-forged from Hitachi Yasugi Shirogami No.1 steel (White Label No.1 steel) and heat treated using the very best blacksmithing techniques.
At approximately 270mm long (10-⅝”) in length, these chisels are essentially smaller versions of our regular Sukemaru-brand atsunomi at 295mm long (11-⅝”). All dimensions are likewise reduced producing a handier, lighter-weight version of the atsunomi on the one hand, or a longer, beefed up version of the oiirenomi on the other, depending on your viewpoint.
Woodworkers with larger hands who appreciate a little longer/larger oak handle, or who need a chisel with a little longer/thicker blade with extra reach, or who need a tool with more heft than the standard oiirenomi, but don’t want the higher price or greater weight of the atsunomi chisel will find these elegant chisels to be real honeys. They are especially suited for field installations and light timber framing, but work well in the shop too.
We offer them in standard widths: 6, 9, 12, 15, 21, 24, 30, 36, 42, 48 and 54mm. Custom widths are available upon request.
We stock these chisels fitted with either Japanese White Oak or Red Oak handles. These woods are a little denser and tougher than their American and European counterparts, although the appearance of the grain is not especially exciting. I think this is a fair trade in the case of a tool handle that must routinely endure many thousand violent impacts, don’t you?
Pricing
Consistent with our policy of providing the best-performing tools possible to professional woodworkers at a reasonable price, and knowing that inflation is causing prices of all products to rise universally nowadays (ouch!), we worked with our blacksmith, sharpener and handle maker to keep prices as low as possible. As a result of those efforts, our Hantataki chisels are about half the price of Sukemaru’s atsunomi chisels, and just a few pennies more than our standard oiirenomi bench chisels making them an excellent value. In other words, it’s a chisel that is almost as big and tough as an atsunomi, but for the price of an oiirenomi.
The level of the fit and finish is not as high as our Sukemaru brand chisels, which is the prime reason for the reduced cost, but cutting performance, edge durability and ease of sharpening is equivalent to our other chisels, that is to say, excellent.
In summary, this is a medium-sized professional-grade chisel at a bargain price.
You can confirm pricing and availability, and view more photographs by clicking the pricelist at this link. Not sure how long we will be able to continue to provide them at these low prices, so gittem while they’re hot!
YMHOS
The grounds of the Imperial Palace in Tokyo seen from a bridge over the moat.
If you have questions or would like to learn more about our tools, please click the “Pricelist” link here or at the top of the page and use the “Contact Us” form located immediately below.
Please share your insights and comments with everyone in the form located further below labeled “Leave a Reply.” We aren’t evil Google, fascist facebook, or thuggish Twitter and so won’t sell, share, or profitably “misplace” your information. If I lie may the Emperor decline to invite me to his birthday party (again (シ)).
Practice doesn’t make perfect if you’re doing it wrong.
Frank Sonnenberg
This is the first in a series of articles about the tools and techniques used for laying-out joints in wooden cabinetry, joinery and furniture. They were not invented by your humble servant; Indeed, they are older than all the pyramids. I have no doubt Father Adam taught them to some of his sons and daughters.
We will delve into the specifics of layout tools in future articles, but in this article your humble servant would like to discuss an ancient layout concept sometimes called “Reference Surfaces.”
Reference Surfaces
The purpose of employing reference surfaces is simply to limit Murphy’s influence on the craftsman’s efforts, thereby improving the precision and speed of his work, saving time, material and in the end, yielding a better product. Why is this a concern? Simply because, as Gentle Reader is no doubt aware, Murphy’s Law of Thermodynamics ruthlessly dictates that errors in layout do not cancel each other out, as the optimists and theorists naively assert, but rather accumulate in the direction of maximum chaos. Thus it has always been.
There is a old Architect’s saying that goes something like this: “Cut to fit, paint to match.” There’s another version used by finish carpenters that better reflects reality in the field: “Cut to match, paint to fit.” Indeed, the painter is often the finish carpenter’s best friend hiding many layout and fitting mistakes with his clever brush and globs of paint. Thank heaven for spackle (ツ).
But the wise professional woodworker will hone his skills so that the concealing spells and potions of the painter are not necessary to make his work look acceptable because, while many errors can be excused, the open mouths of sloppy joints will gleefully mock the craftsman that made them for as long as they exist, even from underneath thick coats of latex paint. Implementing the concept of Reference Surfaces during layout is one sure way to reduce this shameful razzing. But I digress.
A Reference Surface (RS) is usually a flat surface or plane on a piece of material, be it cardboard, wood, stone or steel, that a craftsman intentionally designates for layout purposes.
To help explain why reference surfaces are useful let’s consider an example using them to make a typical component in a door or cabinet, such as a stick or board with a rectangular cross-section and a tenon on one (or both) ends.
The Primary Reference Surface
It is usually most efficient to prepare and mark a Primary Reference Surface (PRS) on a workpiece first.
Begin by sawing, milling and/or planing the stick under consideration so all four long-grain surfaces are flat, adjoining surfaces are square (90˚) to each other, and opposing sides are parallel to each other. Easy stuff right? Maybe not, because in the real world, it is time consuming and often wasteful to try to make materials perfect, at least when there are cheaper, quicker alternatives. How perfect do the dimensions of our materials really need to be? And even when we aim for perfection, how can we consistently deal with the small discrepancies that always creep into human efforts when subjected to cost and time pressures? But I digress again. Back to our stick of wood.
The first step in making the stick ready for layout of a tenon is to make one at least one long-grain surface as straight, flat, and free of wind (twist) as we can. This is not difficult to accomplish using handplanes or even a well-setup thickness planer. The stick should initially be slightly oversized, of course. If Gentle Reader is not yet able to make one face of a stick straight, flat and free of wind using handtools alone, I encourage you to practice until you can. You will succeed.
The essence of quality control is to constantly compare the results of one’s efforts against reliable standards. You can check that the surface you intend to designate to be a Reference Surface is flat using a precision, beveled or thin straightedge and/or a flat surface such as a flat workbench top.
To use a straightedge, place its edge along the surface, hold it up to a light, and check for light showing between the straightedge and the surface of the stick. So long as the straightedge is truly straight, not dinged or dented, and not too thick, human eyes can easily detect light passing through extremely narrow gaps (kick-ass “hyper-acuity”). Perfection is neither necessary nor attainable, but it should be pretty darn close.
Now repeat this step with the straightedge laid between diagonal corners. If the gap between the surface and the straightedge laid along the diagonals is not identical (ideally non-existent), or the straightedge won’t contact both corners at the same time, then you may have discovered some wind (twist). This technique works especially well for wider boards, but not so much for narrower sticks. So what’s another way to check for wind?
To quickly check if a stick or board is flat, simple place the board or stick on the truly flat top of a workbench or atedai, press down on the ends with one’s fingertips, and pay attention to see if the stick or board rocks. Then flip it over and repeat. If it rocks, it isn’t flat. This is a quick (takes only a few seconds) and reliable technique, one that Gentle Reader should perfect, but the information it can convey is limited.
To check for wind, tap the corners of the board or stick with your fingertips while the board is resting on a flat benchtop. Flip and repeat. If the board or stick rocks on its diagonals, then you have discovered wind. Once again, fast and reliable, but not extremely precise. Use a straightedge to perform a more precise check for flatness and wind.
By the way, anyone intending to do high-quality woodworking (especially when using handtools) needs a stiff, flat workbench or atedai (The Atedai Part 1, Part 2) of some sort because this working surface not only helps us to plane flat, twist-free wooden components, it also helps us quickly identify areas of wooden components or assemblies that are not flat or that are twisted as described above. It is the woodworker’s most important jig.
After checking for flatness and wind, use a carpenter’s pencil or lumber crayon to mark high spots and directions of twist. When everything is marked, examine the board and make a plan of attack for your plane. The subject of how to plane a board efficiently is worthy of another dedicated article, but I have abbreviated the process here.
For now, please remember to always plane only the high spots on the board/stick without touching the low spots. Think about what this means and how you might go about doing it because it takes self-control to develop a plan and then tame one’s inner badger to execute it efficiently, something many newbies without a master or senpai nearby to slap them upside the head when they err often find difficult to make a habit.
Remember, at this stage we are not yet trying to make the board pretty, just to knock down the high spots without lowering the low spots further.
After all the high spots have been removed and the board is flat and free of wind, only then should we use a finish plane with a true sole, tight mouth and sharp blade to remove all cosmetic defects and make the make the board’s surface shine.
Now that we have one surface flat, free of wind, and clean we will call this our Primary Reference Surface and mark it.
Marking
There are as many ways to mark a woodworking project as there are to cook beans, but they all accomplish the same thing.
I have learned several techniques over the years, but find myself using Krenov’s Cabinetmaker’s Pyramid most frequently (if you haven’t yet read JK’s book “The Impractical Cabinetmaker,” you should). Whichever marking technique you employ to identify the location and orientation of each component in a woodworking project, be it ABC, 123, イロハニホヘ、the palindrome “KAYAK,” odd-shaped butterfly wings, or some other mushroom-inspired scribble, it must consistently make the orientation of the piece of wood in the finished product clear at a glance (up, down, top, bottom, front, back, right side, left side, etc.). Make this mark on the freshly completed Primary Reference Surface (PRS). For cabinetry, joinery, furniture etc., a pencil seems to work best. In the case of dark woods, white or yellow lumber crayon works too. Six of one half-dozen of the other.
Another thing Gentle Reader should consider when marking the components of your project is the visibility of each component. For example, when planning a project such as a cabinet, especially one where visible grain and beautiful color are important features, it is often beneficial to place the most beautiful pieces of wood in the most important, most visible locations in a project. Once again, this demands some planning.
Likewise, the joints where components meet in high-visibility locations , such as mortise and tenon or dovetail joints, need to form flush surfaces when assembled. This typically means placing references surfaces in the finished product where they will be most visible, and have the fewest defects, or the most beautiful grain, or a complementary grain pattern.
On the other hand, this planning process should also orient the visible surfaces of component that exhibit less than perfect surfaces, or have less than perfect color, grain, joints, and even obvious defects, so they are concealed inside the cabinet. While not the pinnacle of workmanship, this is a compromise that has been standard operating procedure forever, especially where funds and/or time are limited.
Taking this marking concept one step further, it is useful to combine reference surface markings with identifying marks for each individual component. If you have a good marking plan and execute it consistently, you will always know at a glance which component belongs in which location and how it is to be oriented (up, down, right, left, front, top, bottom, back, right side, left sides, etc.) during assembly. Confusion during a complicated assembly is to be avoided.
The cabinetmaker’s pyramid combined with simple letter annotations is useful, but not the only solution by any means, For example, inside the piece of the pyramid applicable to a component, a corresponding annotation such as the following can be made: F = front, B = back, R= right, L = left, P1 = first panel from front/right, P2 = second panel from front/right), etc.. When things are more complicated, it helps to name each piece on the drawing, give it an abbreviated designation, and mark that designation on the component. Anyway, enough on this subject.
The Secondary Reference Surface
Assuming we are making a stick or board with a rectangular cross-section, as mentioned above, we next need to make a partner reference surface I like to call the “Secondary Reference Surface” (SRS), adjacent the PRS and oriented 90˚ to it. It too must be flat and free of wind as it will be an important reference surface for layout purposes.
If you are using an electric thickness planer, go ahead and plane to the appropriate thickness now, but always check to make sure the stick/board is truly flat, free of wind, and its ends are free of snipes. May the gods of handsaws guide your hand.
I strongly suggest you use your vernier, dial, or digital calipers to actually check thickness because, without putting too fine a point on it, Murphy’s pointy purple pecker is always promiscuously probing.
If you are thickness planing by hand, I suggest you begin making the SRS by shooting one edge, as described in the next section.
Shooting the Edges
Enma, the Buddhist King of Hell, presiding over festivities. A good time was had by all!
Many (but not all) of the gurus and well-published scribblers who shill for the woodworking tool manufacturers (may the Lord Amidha give them a few years roasting over Lord Enma’s fire on a barbed spit before tossing their sorry souls back into this miserable existence as termites) advocate shooting edges by clamping a board or stick into a vise and then balancing a jointer plane on the narrow side edges to plane the edges square to the wide faces. This technique works, sorta, but unless one is planing thick boards, it is often slow, unsure and silly. Here is the way I was taught in Japan and the way I do it now. Gentle Reader is free to choose, but I suggest it would be less than thoughtful to ignore this intelligent, efficient and nearly fool-proof technique.
This technique relies on the reliable precision of two common tools. The first thing to check is that the angle between the sole and side of the handplane we use for shooting (usually a jointer) is exactly 90˚degrees (do you really have a tool that will precisely check 90˚or do you just assume you do?). Of course, the blade extending past the mouth must also form a perfect 90˚ angle with the sole. These are common standard tolerances any woodworker worthy of breathing air must learn to maintain. If your handplane’s tolerances are out of wack, best to correct them first.
The second precision tool you need is a workbench, atedai or planing beam with a truly flat, wind-free top working surface. This too is a standard tool a woodworker who intends to perform high-quality work needs.
The Japanese atedai and planing beam frequently have a board a little wider than than the thickness of the handplane used for shooting screwed to its edge (usually the right-hand edge) which is stepped down from the atedai or planing beam’s top surface. The step is usually just a little more than the thickness of the plane’s cheek. One places the board or stick on the top of the atedai or planing beam, holds or clamps the workpiece in-place, rests the jointer plane’s side cheek on the ledge, and while pressing it towards the workpiece, pulls it to plane a flat, wind-free surface. Please note that this is possible because the top surface of the atedai or planing beam is flat, and the plane’s sole/blade are oriented 90˚ to it, so a square edge can be shot easily and reliably without any silly antics.
There are a number of wooden/plywood jigs used in by Japanese craftsmen in place of the ledge. One of those works well with the Western-style workbench too.
All it takes is a flat wind-free piece of plain plywood or a plain solid wood board (I call it a “shooting board”) at least as long and wide as the workpiece to be shot, and a little thicker than the cheek of the plane. Much thicker is not efficient.
One lays this shooting board on top of the workbench (or atedai or planing beam). The workpiece in turn is laid with its PRS or SRS side facing down on top of the shooting board with the edge to be shot projecting past the the edge of the shooting board a small amount. Clamp these two boards to the workbench, atedai or planing beam with C clamps or other holdfast mechanisms. Stops or benchdogs projecting from the benchtop are useful too.
Then, after checking that the blade of your jointer plane is projecting the right amount and angled properly, simply lay it cheek-down on the work surface, against the surface of the workpiece to be shot, and pull or push it to plane a shaving. Voila: a straight, flat, wind-free edge at a 90˚ angle to the PRS or SRS.
Of course, before making shavings you will have examined the stick/board and made a plan in your head for shooting it efficiently. You will have also marked a straight line to plane to, and of course you will have an accurate square and straightedge on-hand to check results.
This technique is quick, reliable, extremely precise, and can handle boards as long as your workbench, atedai or planing beam can accommodate without any amorous monkey-football theater.
In any case, the goal is to create a surface (SRS) that is straight, flat, free of twist and square (90˚) to the PRS. You can mark this surface however you see fit, but it is important that you be able to tell its relationship to the PRS at a glance. I do this by drawing diagonal lines along the PRS ending at the edge adjoining the SRS, and then continuing those line onto the SRS. Simple stuff.
Dimensioning to Final Width &Thickness
Now that we have established and marked our a Primary Reference Surface and Secondary Reference Surface, we have two options before us. One option is to use a marking gauge to layout the width of the stick/board on all four edges and saw/plane it to final dimension, or to use a marking gauge to layout the thickness in preparation for sawing/planing the stick/board to final dimension. The choice is up to you, but your PRS and SRS will make the job quick and certain because the hard work of checking and planning were done right, done early and therefore need not be repeated.
Relative Precision
It is worth observing at this point that, once you have accurately established a PRS and SRS, the surfaces opposite each of them often do not need to be precisely dimensioned. Indeed, this has historically commonly been the case when craftsmen made products, whether of wood, stone or steel, with surfaces where precision and/or appearance was unimportant. A word to the wise.
About now, thoughtful Gentle Reader (may the hair on your toes ever grow long) may be asking yourself just how the heck to go about doing the rest of your layout if two out of four surfaces of a workpiece are not precisely dimensioned. That you ask this question is clear evidence of your astonishing intelligence!
The answer is simple. When measuring a distance or making a layout line, whether using a scale, divider, caliper or marking gauge, always do it from either the PRS or SRS, not the less-precise surfaces. This will yield maximum precision with minimum effort and less opportunity for Murphy to pointedly intervene.
For example, when marking the width, thickness or length of the stick/board in the previous section using a marking gauge or marking knife/square (tools of inestimable value), you should always rest the fence of your marking gauge/marking knife & square against either the PRS or SRS. In this way, so long as you have not over-imbibed planing fluid, and have held up your end of the job, the layout line your gauge/marking knife & square makes, and the plane delinated by two such lines, will be as straight, flat, free of wind, and square as are the PRS and SRS that guided their formation. I recommend you make this procedure a habit.
Laying-out The Tenon
Our stick or board should now have two surfaces (the PRS and SRS) that are precisely straight, flat, free of wind and square to each other. The sides opposite these two surfaces should be pretty straight, flat, free of wind and square to each other too. Remember, perfection is unattainable and seldom really necessary, but so long as we have a good PRS and SRS, all will be well. With this established, we can now layout a tenon one end of our stick or board.
The first task is to cut the stick/board to length while at the same time making flat, square ends.
Please take note that the order of the steps in this process is important to ensure maximum precision in imprecise wood with minimum effort.
Begin by making a small tick mark with the very sharp, pointy corner of our marking knife where we want the stick to end.
Then, with your accurate, hardened stainless steel square at hand, set the point of your marking knife into this tiny cut and slide the blade (thin part) of your accurate, precision square (most are neither accurate nor precision, and they are often shaved, dinged and practically knackered) against the flat of the marking knife. The beam (the shorter, thicker part of the square) must rest firmly against either the PRS or SRS, not their opposing surfaces. It really doesn’t matter which reference surface you begin with, but for this example, let’s say we pressed the beam against the PRS. With your marking knife guided by your square’s blade, make a straight, clean cut across the width of the SRS taking care to make the cut vertical and not angled right or left.
Next, place the beam of your square so it is pressed against the SRS this time, set the sharp little point of your marking knife into the cut you just made, and slide your square so its blade is stopped against the point of your marking knife and spanning the width of the PRS. Note that it is the marking knife, indexed in the skinny cut you made previously to the SRS, that determines the location of the square’s blade, no squinting or straining necessary.
Now repeat for the other two sides, but be sure to index your square only from the PRS and SRS. This means you will need to change the way you hold your square.
I would like you to perform an experiment to confirm why you should use reference surfaces and your square and marking knife as described.
Take another stick, one that has not been precisely trued, and layout or “spin” a layout line near the end as if in preparation for cutting it to final length, but instead of using any reference surfaces, use the square and marking knife exactly the same for all four sides, but when marking each new line, index your marking knife in the layout line you cut on the previous side. Check to see if there is any gap between where the the layout line on the last side meets the layout line on the first side. Often there is a noticeable gap, and the wider the sides, the greater the gap will be.
This gap can be caused by either; (1) Using a square that is out of tolerance (a common enough problem); or (2) Sides of the stick/board that are either not straight, flat, or square or parallel to each other.
Think about the errors that can creep into a project and how they might accumulate as it progresses. Then consider how accurate reference surfaces can help prevent these errors. Most people’s minds boggle just a little bit the first time they perform this test and come to understand the likely consequences, and realize how often they have sabotaged their own efforts.
Now that the stick is the right length and we have clean, square ends, let’s layout the shoulders of the tenons.
Cutting the Stick to Final Length
You can then use your handsaw to cut the stick to length. It need not be a special saw unless the end of the tenon will be exposed, but do remember to keep the saw’s point inside the marking knife’s cut, with the sawcut to the side of the marking knife’s layout line. This is not a difficult skill to develop, but it is essential, so please make the effort.
Laying out the Tenon’s Shoulders and Cheeks
Laying out the tenon’s shoulders is simply a repeat of the steps listed above, but don’t use a saw just yet.
With the tenon shoulder line marked, next use a marking gauge to layout the cheeks of the tenon. Once again, when making all these layout lines, index the marking gauge’s fence against the PRS and SRS only. Please also remember that, unless you are using a double-bladed mortise gauge, you will need between two and four marking gauges to make all the layout lines without resetting your single marking gauge. I highly recommend having multiple gauges on-hand so you don’t need to fiddle with settings midway through a project because fiddling with marking gauge settings is a common path for errors to sneak into layout efforts.
Sawing the Tenon’s Shoulders and Cheeks
With all the tenon’s layout lines made, you now have the choice of cutting either the shoulders or cheeks of the tenon first. I prefer to cut the shoulders first using a high-quality dozuki saw, a tool intended, in fact named, for this task because an error here is irreparable. Nothing beats a good dozuki saw for this job. But it really makes no difference which you cut first so long as you stop each shoulder cut before severing fibers in the finished tenon.
Your humble servant recommends using a high-quality, very sharp, fine-toothed rip saw such as a hozohiki saw or tenon saw to cut the cheeks.
Some woodworking gurus/scribblers and BoobTube Geniuses insist that one must cut short of the layout line, leaving the the tenon short and fat, and pare to final dimensions using a chisel, or even a plane blade. This is pure, time-wasting, Mickey Mouse codswallop. Anyone who calls themself skilled in woodworking with handtools must be able to saw cleanly and precisely right to the layout line so that paring is only rarely necessary. If you can’t yet do this already, I strongly urge you to practice this bedrock-basic skill until you can. The article at this LINK may be helpful.
That said, I do sometimes use a 90˚ wooden jig, similar to a large, thick square, to save time when cutting deep shoulders. Perhaps we can discuss such aids in a future article.
Conclusions
I hope this article has been helpful in increasing Gentle Reader’s understanding of the usefulness of Reference Surfaces, and how to plan, mark, make and use them.
I have tried to condense a tremendous amount of information into this post, not just about Reference Surfaces and using them for layout, but about the immutable laws of error accumulation, dimensioning material, edge shooting, workbench tops as jigs, layout marks, orienting materials in a project based on appearance goals, and even simian sporting events (ツ).
I apologize, however, for the somewhat jumbled presentation.
I also apologize for the lack of photographs and illustrations, but your humble servant has many pressures on his time, and most of this article was written during a long flight between London and Tokyo on an empty airplane. It was so empty I was unable to resist the temptation to lay down across the center row of seats and saw some wood. Don’t worry, I cleaned up the sawdust (ツ)。
In future articles in this series we will discuss more tools and techniques for laying out and cutting basic woodworking joints. In the meantime, please remember that Practice Makes the Master.
YMHOS
Practice makes the master
If you have questions or would like to learn more about our tools, please click the “Pricelist” link here or at the top of the page and use the “Contact Us” form located immediately below.
Please share your insights and comments with everyone in the form located further below labeled “Leave a Reply.” We aren’t evil Google, fascist facebook, or thuggish Twitter and so won’t sell, share, or profitably “misplace” your information. If I lie may all my all my layout tools lay down on the job.
Woodworking matters. It’s more than a pastime or hobby—being a woodworker means that you know the satisfaction and pride that comes from using your hands and mind to build beautiful, functional objects, and that you’re as interested in the process as the outcome. Amid the speed and chaos of the modern world, woodworking gives us a place where we can slow down, pay attention, and take the time to do things right.
Aimé Ontario Fraser
Your most humble and obedient servant is exceptionally proud to have never made any project published in a woodworking magazine, with one exception: The Michael Dunbar Windsor Shop Stool. This is the story of my version of his stool. With some twists.
Policy Statement
I have a policy: While I have no qualms about showing portfolio pictures of past work to prospective Honored Clients, I don’t publish, distribute or email images of work done for HC’s. The reasons are simple. First, to avoid violating their privacy, I need to get their permission in-advance, in writing, which can be a pain. Second, while showing pictures of their property may not offend them now, it may in the future. Misunderstandings can occur even when backed-up by a piece of paper.
I also dislike bragging about my work in public, and nothing can be more public than the internet. But I am making an exception with this post because the subject is something I made strictly for myself, and it is decidedly ridiculous. If Gentle Reader doesn’t find it interesting, perhaps you’ll find it amusing. I invite you to snigger gracefully at your humble servant’s atrocious efforts.
Pragmatic Contrarianism
The title of this post includes the strange term “Pragmatic Contrarianism.” What does it mean? It’s a term I invented, I suppose, but the intended meaning is to consistently examine problems from an angle opposite of what is considered conventional, and then to formulate workable solutions based on an analysis of those observations, without regard to whether or not the resulting conclusions and the solutions implemented contradict standard theories and/or common practice, so long as they achieve the designated goals and objectives more efficiently than the conventional solutions. It does not mean an uncontrolled compulsion to be idiotic, disruptive, argumentative, deceptive, sexually abusive or psychotic like the management and staff of the Communist News Network.
A contrarian is a person who takes an opposing view, especially one who rejects the majority opinion.
One definition of pragmatism is as follows: “A reasonable and logical way of doing things or of thinking about problems that is based on dealing with specific situations instead of on ideas and theories.”
A pragmatic contrarian therefore is a person who actively seeks solutions different from standard convention, and implements those solutions in a way that yields desired performance and functionality.
This stool is your humble servant’s expression of this concept.
Motivations
A good workshop stool must be more than just simple furniture: it is a woodworking tool in and of itself, especially in a small shop, where it must serve not only as a butt rest but as a step-ladder, tool rest, sawbench, parts table, paint-can holder, cat bed, and even weight-spreader during glueups. These jobs require a stable, durable and reliable tool. Lightweight is a big plus too. And bench kitties always demand comfort of their servants (that’s me and thee).
Let me begin by telling you why I needed to build a stool. Perhaps you share some of these same reasons. Perhaps the solution I struck on will give you some ideas. Stranger things have happened.
Since moving to Japan, my workbenches have been in storage back in the U.S., so while stationed on the remote island of Guam planning construction projects for the Japanese government, I built one for the little woodworking shop I set up in my garage for making sanity retention components. Of course, I needed a stool too, so I considered my options.
On the US mainland I used cheap wooden stools produced in Eastern Europe or China that became rickety as quickly as a newly-elected politician’s moral convictions, so I was in the habit of tossing them each time we moved and buying a cheap replacement at the new location. Sigh… Would that morally-decrepit politicians were so easily disposed of.
Thinking back, those stools were clunky, ugly, top-heavy, and too tall requiring me to cut them down to a height convenient for hammer and chisel work at the workbench. This time I wanted a lighter, more stable, more comfortable, more attractive stool that would provide good service past my lifetime instead of being temporary mass-produced garbage-in-training. There aren’t many stores on the island, selection is bad and prices are high, so after shopping around I decided to build a lifetime piece of furniture myself this time instead.
Now, I am not a chairmaker, but lack of experience never stopped me from making a fool of myself before, nor did it this time.
The Design
As I contemplated the design of the stool I remembered seeing an interesting example in an article by a professional Windsor chair maker, instructor, and author named Michael Dunbar, and decided it would be just the ticket. Of course, true to my pragmatic contrarianistic principles, I modified the design to fit my needs, tools, and peculiar sense of beauty.
I do not own, have never owned, and do not want to own a wood lathe, so I didn’t even consider attempting the elegant turnings that beautify every component of Mr. Dunbar’s stools. Being a contrary sort of fellow, I decided that instead of trying to imitate his lathe-work, I would design my stool so that not a single piece of it could possibly be produced on a lathe, not even by mistake. And since I didn’t have any stationary power tools with me on the island, the design ensures the final shapes could not have been made on a tablesaw, bandsaw or shaper. Every component is shaped entirely by hand, no exceptions. How’s that for pragmatic contrarianism?
The legs are designed similar to the birdcage style seen in Mr. Dunbar’s simplest design except for being octagonal. I am fond of the birdcage style, enough so that I commissioned a dining room set in cherry wood from an Amish furniture maker back when we lived in Ohio. In this case, however, the legs all have different dimensions, thinner in some places and fatter in others. No rounded swells, but closer in appearance to irregular octagonal bamboo segments. None of the curves between segments are uniform. The picture does not do justice to the artistically (ツ) chaotic angles and uneven surfaces.
An octagon has 8 angles of 45 ° each, so, consistent with my contrarianistic aspirations for this stool, I made each angle just a little less or a little more than 45°. It looks kinda sorta strange until you carefully examine the stool and realize that it is definitely strange. Perfect!
Just to extend the contrarianist principle to its ludicrous conclusion, I made all the angles between seat and legs slightly different too. It would have been a lot easier to make them uniform, but what’s an adventure without some pointless struggle? At least this adventure didn’t leave me dead in a pile of garbage on K2!
Like Mr. Dunbar’s stool, the seat is hollowed out, but instead of being circular, it’s octagonal and sculpted to look as if it has a segmented joined perimeter covered with worn green leather sagging over 8 ribs radiating from the seat’s center. There are no segments, no ribs, and of course, no leather, just a single board seat, but I carved 8 little ridges into the seat to suggest the existence of these supporting ribs, just another detail that could not be made with a lathe.
The green color of the seat is intended to imitate the green leather commonly used for furniture in days of yore.
The Construction
The wood I used was exceptionally-dense Mahogany from a board I found fallen behind the racks of an old lumberyard on the termite-infested rock that is Guam. The figure was nothing special, but my hand plane turned the dirty grey board a beautiful dark red color. Better than a paintbrush. If I recall correctly, it was an exceptionally large and clear 8/4” x 23” x 14’ board. I had already used most of it for other projects by the time I got around to making this stool, but had just enough scraps left for the job.
I made the stool without using power tools of any kind, just handsaws, handplanes, spokeshaves, chisels, knives, Auriou rasps, and my Father’s old brace with fine-screw Jennings bits. I cut the beading detail using carving chisels. It was fun, partly because there was no customer to complain (not even the Mistress of the Blue Horizons), and partly because it was something new.
I did not sand the wood but left all the tool marks in place. Mecha retro.
I followed Mr. Dunbar’s advice and finished the stool with three color coats of red, green and black milk paint topped with a coat of thinned flat polyurethane. This was my first experience using milk paint and I loved the results. I highly recommend it.
After applying the milkpaint, but before the PU topcoat, I distressed the finish with files and sandpaper, especially at high-wear areas, exposing the various layers of color unevenly to produce the appearance of a chair that has been used, abused and repainted in different colors several times during its lifetime.
Applying multiple layers in different colors is not an original idea, but it is genius. Each coat creates a distinct layer of color over the uneven toolmarks which remain on the wood’s surface.
I have no interest in reproducing antiques, but the colors are charming to my eye and there is something to be said for accelerating the process of perceived wear from shiny-and-new to worn and patinated instantly bypassing the grungy-looking intermediate period. Besides, no matter how much I use it and abuse it, additional wear and damage have only changed its appearance without making it perceptibly worse. I can’t think of another applied finish that does this better.
And this finish has ensured that as the stool has become worn, scratched and paint-splattered over the years in my several shops it’s character has not been damaged but only improved. Would that my face had improved over the years to the same degree instead of growing more purple warts sprouting vigorous clumps of long black hairs
Another advantage of traditional milk paint (v.s. the latex-based faux milk paint sold in home-centers and hobby stores) is that, since it contains large amounts of ground minerals, it cures to a hard surface that is surprisingly wear resistant — certainly more abrasion-resistant than standard latex, acrylic or polyurethane coatings commonly used for finishing wood. Excellent for rough use in a workshop.
I don’t have specialized tools for coning mortises and tapering tenons, so the leg/stretcher/spreader joints are simple round tenons fitted forcefully into tight round mortises, pared larger in diameter at the top, saw-kerfed and wedged in-place.
The geometry of the seat to leg joints places the leg/stretcher and stretcher/spreader joints in tight compression ensuring they will never loosen or come apart unless the seat fails or the tenons break off. So far so good, knock on numbskull.
Performance
Windsor chair leg geometry is genius, if a bit tricky to assemble. Not only have the joints remained tight, but 13 years later I can still strike any part of the stool with a mallet and it rings like a wooden bell even during Japan’s dry winters and humid summers despite being built in the unchanging 85% relative humidity of Guam. Amazing.
I was doubtful at first, but Mr. Dunbar’s seemingly-unlikely assertion that a hollowed-out seat is more comfortable than a flat seat for a workbench stool was curiously correct. It’s not only more comfortable but more stable because instead of being perched on top of a flat surface, my posterior fits down into the seat giving me better purchase, another application of the time-tested “ butt clamp“ principle. This extra stability is a big advantage when using handtools at the workbench. And it has the added benefit of saving sleeping bench kitties from the indignity of sliding off onto the shaving-strewn floor. Perish the thought!
No matter how many scrapes, scuffs, dents, paint drips, or other abuse this stool has suffered, like a good pair of boots it has taken them all in stride without complaint
It remains to be seen, but I think this stool just may meet my 200-year service lifespan goal. I intend to hang around and personally confirm this, of course, but please remind me in 187 years to post the results on the subspace net if I forget.
If you want to try your hand at the basics of Windsor chair making while gaining a shop stool superior to any other type—one with the potential to become both a useful tool as well as a family heirloom and high-demand bench kitty bed—you might want to give Mr. Dunbar’s stool a try. Or, even better, be a fellow pragmatic contrarian, run with his design concept, and make your own interpretation.
And don’t forget to sign and date the seat’s underside. In 200 years some of your descendants might be curious about who made it, just in case you’re not around to remind them.
Lessons Learned
You might take away several lessons from this story of a silly stool. Perhaps the first one is that instead of spending hard-earned cash on future landfill stuffing made in the PRC, you can build the furniture you need for your house and workshop yourself at less cost and without powertools.
You don’t need to go into debt or put off making that table or chairs or bed until you can afford or have space for a tablesaw, bandsaw, jointer, lathe and thickness planer. And you don’t need to save pennies for years to buy expensive hardwoods, just be pragmatic and design the furniture around the tools you already own and the wood you can get your hands on cheaply.
In fact, the first furniture I made as a married starving student with a newborn baby was a knock-down coffee table, two end tables, a sofa and a loveseat from 2×4 DF/Larch concrete formwork I salvaged from the construction jobsite I was working as a carpenter in Las Vegas during Christmas vacation. The only hardware I used was a mix of left-over door hinge screws (I hung several hundred doors in a hotel construction project that winter) and used lag bolts scrounged from the guys who installed the rollup doors at the jobsite’s loading dock (thanks, guys!).
I worked on that furniture set nights and weekends using the concrete slab in front of our dingy Las Vegas apartment and three 8″ high horses as a workbench and only limited handtools, an electric drill, and a sparking, aluminum-bodied router. I finished it with WATCO danish oil.
We bought discount cloth and foam from an industrial upholstery supply house, and my diligent and intelligent wife sewed all the cushions using a friend’s sewing machine. The neighbors thought I was strange, and of course I was, but they kindly tolerated the energetic college kid with the cute Japanese wife who was always making sawdust and sweet-smelling plane shavings out on the sidewalk as they provided sage advice while smoking their cigarettes and drinking beer in the gloaming.
I could disassemble the entire set to fit flat in our VW van when we moved, and it served us well for seven years for only the cost of some fabric, upholstery foam, sandpaper, and a quart of Watco Danish Oil wood finish.
If, like me, you are pragmatic and sometimes a wee bit contrarian, you might want to use your handtools to make something that couldn’t possibly be made by stationary powertools. After all, what’s the benefit of owning and being proficient with handtools if everything you make with them looks just like the stuff sold at the local “Furniture Warehouse” or whatever they call the purveyor of discount garbage-in-training in your community?
Another possible lesson is that, depending on the design of the furniture you make and how it mutates during the fabrication process, you can use classical structural details and design elements, such as durable mortise and tenon joints and the clever details of the Windsor chair to turn inexpensive wood into family heirlooms that get better with age. Imagine that, the victory of intelligence, adaptation and diligence over money. I like it a lot!
You don’t need to spend a lot of money or have lots of space or own fancy powertools to have lifetime furniture with character so long as you are willing to be pragmatic and a little contrary.
Your humble servant (the devastatingly handsome fella on the right) discussing a construction project with a Beloved Customer of the Fae. Fashion is my life, as you know, but do you think I might have gone just a tad overboard with the hardware?
If you have questions or would like to learn more about our tools, please click the “Pricelist” link here or at the top of the page and use the “Contact Us” form located immediately below.
Please share your insights and comments with everyone by using the form located further below labeled “Leave a Reply.” We aren’t evil Google, fascist facebook, or thuggish Twitter and so won’t sell, share, or profitably “misplace” your information. If I lie may termites eat all my wooden furniture.
A famous wood block print by Katsushika Hokusai titled ” Mount Fuji Seen from the Mountains of Totomi,” one scene in thirty-six. With pre-big-bang Mount Fuji in the background, a group of four sawyers, and judging from the mother and baby in the foreground, probably including at least one family, are sawing boards from a huge timber on the very mountain where the tree was felled. Two men are sawing away with maeibiki ooga saws, one from above and another from below, while a third sharpens a saw underneath. Clearly, OSHA approval was not obtained for this working arrangement, oh my! They probably slept in the rough shelter erected at the left. A brutal, if scenic, lifestyle with abundant fresh air and fragrant sawdust.
Perfection is a necessary goal, precisely because it is unattainable. If you don’t aim for perfection you cannot make anything great, and yet, true perfection is impossible.
Leonard, The Outfit
Cutting joints connecting one piece of wood to another, such as mortise and tenon joints, bridle joints, dovetails, etc. using only handtools is not difficult, but most people find, at least initially, that executing them to fit together tightly without slop or unsightly gaps can be challenging.
The ability to routinely and quickly cut tight, workman-like joints with a handsaw is a critical skill for the professional that specializes in making limited runs of custom furniture and casework because including exposed joints not only sets his products apart from mass-produced dreck, but the apparent precision of those joints is a direct, long-term reflection of his standards of quality. And while it may not be a critical skill for the amateur who produces high-quality woodwork, it is nonetheless extremely satisfying, especially if the cabinets, furniture or casework he makes will remain in his house or with family where any poorly-fitting joints will silently laugh at him with “open mouths,” as the Japanese saying goes, over many years. Your humble servant loathes and fears such mocking whispers!
So, how does one go about improving one’s skill with handsaws thereby avoiding the sidelong glances and silent, but nonetheless snide, remarks of gaping joints? In this article your most humble and obedient servant will be so bold as to provide some guidelines I have shared with friends and Beloved Customers over the years, but which I have never before compiled into a single document. Please let me know in the comments below if these techniques prove useful.
The Saw
Of course, hand-cut joinery is accomplished using handsaws, tools that vary widely in quality and performance, so it is appropriate to begin this discussion with an explanation of the features a high-performance handsaw should incorporate.
In your humble servant’s well-informed opinion, the handsaw is by far the most difficult woodworking tool for the blacksmith to produce. Sadly, there are few skilled blacksmiths producing handmade saws nowadays, and while new companies producing pimped-out high-priced backsaws targeting amateurs have sprouted up, many of those exhibit performance inconsistent with the high prices their manufacturers demand. Imagine that….
But never fear, for below is a list of key things Gentle Reader should look for in a high-performance, professional-grade handsaw to be used for precision joinery.
The Plate
Whether Western or Japanese, the “plate” of a saw (the piece of sheet steel that comprises the blade) is its most important component. It must be adequately hard to resist bending and buckling, and so the teeth cut into it can be made sharp and stay sharp a long time, but not so hard the blade will crack or the teeth break off. This is a delicate balance. Sadly, most manufacturers err on the side of softer and duller. Sigh…
The best handsaws are made from plain high-carbon steel with a fine crystalline grain structure. Thus it has always been, and for good reason. Sadly, high-quality steel of this sort is difficult to procure nowadays.
Most of the new American and European manufacturers of backsaws, as well as all the Japanese manufacturers of replaceable-blade handsaws, make their saw plates from pre-hardened, thickness-sanded steel purchased in sheets or rolls, metal never touched by a blacksmith. This is a consistent and cost-efficient material that eliminates the need for blacksmithing skills, but it has a few serious limitations that negatively impact a saw’s performance.
In the case of mass-produced Japanese blades with the discolored, hardened teeth, after the plate has been stamped out with dies and a press, or cut to shape with a laser, the teeth are shaped by grinders, set is applied by machine, and the blade is passed quickly through an induction coil formed by two copper blocks charged with high voltage electricity, suddenly heating the teeth in a technique called “shock hardening.” The plate never slows down, and as the red-hot teeth exit the copper-alloy blocks charged by an induction coil, they pass through a coolant spray which instantly quenches them creating a hard, crystalline structure in the metal.
Most Western backsaws are made using similar materials and processes but without the induction hardening step.
210mm Dozuki saw hand-forged by Nakaya Takijiro, the ultimate handsaw for precision woodworking.
Taper Grinding
A high-performance saw’s plate will be taper-ground in at least one direction, with the plate made thinner at the back than at the teeth, providing extra clearance in the cut, increasing as the blade cuts deeper into the wood, reducing friction between wood and plate for a smoother cut with less effort, and reducing the risk of buckling.
Handmade Japanese handsaw blades are of course double-taper-ground, as once were all quality Western handsaws too, but sadly neither replaceable-blade Japanese handsaws nor modern Western backsaws are taper-ground to any degree. John Disston would puke.
Unfortunately, too many modern users of handsaws, wandering in an Instagram world, have become entirely inured to terminal Chinese Logic, such that most are incapable of even considering qualities they can’t instantly infer (correctly or not) from a photograph on the internet. These confused souls deserve our pity.
Gentle Reader would be wise to place his priorities regarding performance above outward appearance, because a prettily-finished exotic hardwood handle, a beautifully sanded/polished finish on a sawplate, and even an eye-catching etched brand contribute neither diddly nor squat to a handsaw’s job of making precision cuts.
Hammer Tensioning
Hammer tensioning is an ancient technique whereby the sawsmith or saw sharpener rests the plate on an anvil and taps the plate with his hammer creating small dents in specific areas. Each tiny dent deforms the metal making the plate slightly thinner at the point of impact while at the same time displacing a corresponding amount of metal away from the point of impact. Being constrained from expanding as much as it wants to by surrounding metal, the accumulated strain of many dents creates internal stresses that tend to make the saw blade wider and longer. Taken too far, these stresses will make the sawplate buckle or oilcan, but if done just right, for all practical purposes the sawplate will remain flat and stable.
Why bother with all this noisy hammer tapping? Clearly Gentle Reader is exceptionally perceptive to pose this question, and accordingly your humble servant quivers with joy at the prospect of clarifying an elegant and ancient mystery, one that is still employed to good effect in high-quality modern circular saw blades as I learned during recent meetings in Nagoya with three of Japan’s largest circular saw blade manufacturers.
So here’s the reason: As a sawblade heats up due to friction in the cut, the metal of course expands, but not uniformly over the blade’s entire surface. This differential heating and resulting differential expansion causes a sawplate that has not been hammer tensioned to temporarily warp, increasing friction in the cut even further, and making the cut wander thereby ruining the precision of the cut, and in the worst case, causing the saw to bind and even buckle betimes kinking the poor unfortunate blade.
The residual stresses produced in a saw’s plate through proper hammer tensioning counteract and cancel out stresses produced in the sawblade through friction heat thereby preventing the plate from buckling, excessively warping, or oil-canning, with the result that the saw will cut straighter and cleaner with less effort even as it heats up.
I don’t know who invented this subtle technique far back in the mists of time, or where, but it is genius-level engineering.
The better-quality Japanese replaceable-blade handsaw makers have taken a page from the circular sawblade manufactures and run their sawblades through a pair of opposed steel rollers which induce stresses in the steel similar to hammer-tensioning by hand. I may be wrong, but I am unaware of any modern Western backsaw makers that either hammer-tension or roller-tension their sawplates, but instead rely solely on the stiffness of the applied back to prevent buckling. Once again, JD would hurl.
Another benefit of hammer-tensioning, and one Gentle Reader can ascertain easily by examining a saw blade in person (but without the back installed) is that the internal stresses resulting from hammer-tensioning make the sawblade much stiffer than it would normally be without adding metal or weight. You can observe this phenomenon yourself by holding a panel saw’s blade by the narrow end with one hand extended out at arm’s length and examining the blade’s sag. A hammer-tensioned blade will sag significantly less than one that has not been hammer-tensioned.
Another easy test for hammer tensioning applicable to panel handsaws is that of bending the sawplate and tapping it with a fingertip producing a musical note that can be varied by changing the degree of bend in the sawplate. In fact, believe it or not, the handsaw was once a popular musical instrument in some quarters in the USA, with all the major saw manufacturers producing specialty musical saws (sans teeth).
In summary, a properly hammer-tensioned saw will be stiffer, will cut straighter, can be made thinner and lighter, and will require less force to operate for the amount of sawdust generated.
The hand-cut and hand-filed teeth of a 210mm Dozuki saw by Nakaya Takijro. The small dings visible near the chin of the blade are the marks left by hammer tensioning.
Teeth
Tooth types and preferences in handsaws vary so widely that little can be said that applies to all. However, Gentle Reader should consider the following when evaluating a handsaw to be used to cut precision joints.
First, assuming the teeth are the desired shape and size and progression, they should be uniformly and extremely sharp, indeed, sharp enough to cut you if touched carelessly. If you place the palm of your hand gently on the line of teeth, you should feel the little buggers trying to grab your skin. Not just one or two of the vicious little teeth should frantically try to eat you, but all of them in contact with your hand should seem eager to nibble because each tooth is either a frightfully-sharp, pointy little knife, in the case of a well-made and expertly sharpened crosscut saw, or a razor-sharp little chisel, in the case of a rip saw. And of course, a well-made and sharp saw is always eager to cut anything and everything it can get its teeth into. Just ask it.
Unfortunately, the teeth of most of the new crop of Western saws made nowadays are, in my experience, poorly sharpened and in need of TLC before they are useable. I say this as someone that prefers Western handsaws for some tasks, sharpens his own saws by hand, has purchased, collected and tested both new and antique Western handsaws over the years, and continues to use the better of them regularly.
In the case of most woodworking tasks, sawteeth need to have some degree of “set” to make the sawkerf wider than the thickness of the plate to reduce friction, binding, and buckling. Indeed, to compensate for a missing taper-grind and hammer tensioning, most modern Western saws are made with excessive amounts of set. This matters because all the extra wood the sawblade must cut to accommodate this extra set is wasted effort turned into sawdust that does nothing to improve speed or accuracy. Therefore, a good handsaw will have no more set than absolutely necessary to get the job done.
This means, of course, that one needs different saws with different set and different tooth styles for different types of cuts in different types of wood. It makes a difference.
On the other hand, if Gentle Reader uses handsaws solely to burn calories, the aforementioned points should all be studiously ignored. (ツ)。
The teeth of a 210mm Hozohiki rip saw hand-forged by Nakaya Takijiro. The hand-filed steel back finished in traditional burnt silk is also visible at the top of the photo. These teeth are specifically designed to meet the demands of professional Japanese luthiers working in exotic hardwoods.
If Gentle Reader is in need of a high-quality hand-forged saw, you may want to consider those made to C&S Tools’s specifications by one of Japan’s last remaining master sawsmiths, Nakaya Takijiro. You can see some of his products at this link.
A 210mm Hozihiki rip saw hand-forged by Nakaya Takijiro from White Label steel No.2. This saw, and especially its teeth, are specifically designed for cutting precision knock-down joints in the hard, exotic woods, such as ebony and rosewood, that Japanese luthiers use to make shamisen, harps, lutes and other traditional musical instruments.
Using a Handsaw to Make Precision Cuts
The overarching guiding principles in using handsaws to make precision cuts are the following:
The Saw: Use a high-quality saw with the features described above. If you don’t yet own such a saw or can’t afford one, and even if you do, educate yourself in blade sharpening, applying set, and in the techniques of straightening sawplates so your saw will achieve its maximum potential performance;
Layout: Layout the cut so there is no confusion about where it starts, where it continues, where it ends, and the angle of the cut. Whenever possible mark cuts in such a way that the sawblade can positively index itself. This means that the sawteeth will fit into the layout line without you having to guess or use a magnifying glass. Marking knives and marking gauges with sharp cutters can produce such layout lines better than pencils and pens. If there is any chance of confusion, include marks in your layout indicating, for example, the side of the line to cut to and where to stop;
Arrangement: Arrange, support and align the workpiece, your body, and your eye to produce only straight cuts with every single stroke. This point is relevant to item 4 below;
Make of Thyself a Machine: More details below;
Attention: Pay attention to make every single stroke accurate;
Stop & Correct: The instant a stroke goes astray or the cut wanders even a little, stop sawing, figure out why, and make corrections, dammit. Not ten strokes or even two strokes later, but instantly. This requires concentration and iron-handed control of your inner squirrel.
Layout
Spend the time to do layout and marking properly, because confusion and uncertainty during the cut will result in reduced mental focus, and often, poor precision. A solid, well thought-out plan combined with a sharp marking knife, a sharp marking gauge, and an accurate, hardened steel square help to make good lines yielding good cuts.
Arrangement
In order to achieve No.4 in the list above, “Make of Thyself a Machine,” you should spend the time and develop the habit of securing the workpiece at a height and angle that will aid the imperfect human body to make perfect cuts. In my case, this means checking the angle of the dangle and using a vise, C-clamp or a butt-clamp to hold the wood down. It also means stopping work to rearrange the workpiece when necessary. I recommend you try various methods to find which one works best for you when making each type of cut.
In most cases, I like to make gravity my friend by positioning and securing the workpiece so the plane of the cut is vertical. My workbench is level, so either Mark-1 Eyeball or a square usually suffice to confirm alignment, but a small spirit level is sometimes helpful too.
For example, when cutting the tails of dovetail joints, I secure the board in a leg vise, and tilt it so the cuts for half the tails are plumb. When done making those cuts, I next rearrange the board in the vise so the opposite sides of the tails are in the vertical plane, and cut them. Perhaps this is overkill, but it is a habit that helps me to consistently make precise cuts with less damage to brain and eye.
The body must be aligned with the cut to avoid stresses and strains from misaligning “The Machine.” A comfortable position is therefore necessary.
If at all possible the eyeball must be positioned so it can see both sides of the cut to not only guide the cut, but quickly detect a wandering cut, because we all tend to get lazy partway through a cut and stop looking, allowing our inner squirrel to chase after nuts with predictable results.
3 sawyers sawing lumber from a timber, one on top, one from below, and another carrying a saw, probably one he has freshly sharpened. At the right, a carpenter with pipe and tobacco pouch hanging from his waist sash (obi) is using square, sumitsubo, and sumisashi ink pen to do layout on the end of another timber. The mother hens at OSHA would simply be clucking with disapproval if they saw this scene in the flesh.
Make of Thyself a Machine
The title of this section is not intended to suggest Gentle Reader should surgically install bionic parts or change their racial and gender pronouns listed in social media to “Synthetic Person.” (シ) No indeed, nothing so “progressive” is necessary (BTW, what is the politically-correct pronoun for a cyborg: Clank or clunk?). Rather, this phrase refers to a combination of techniques that will help even non-cyborgs overcome the erratic tendencies of flesh, sinew and bone in order to produce more consistent, precise results with a handsaw.
To make a straight cut, the sawblade must travel within a single vertical plane during both the cutting and return strokes. While obvious, this is where nearly all people screw up, always when learning how to use a saw, and in most cases, forever. But we can do better.
If Gentle Reader will pay close attention when making a cut with a handsaw, you will notice that the hand, and consequently the saw handle, tend to move in an arc right and left in a horizontal plane as seen from above. This movement is a result of naturally flexible linkage between hand, arm and shoulder that transmits the force generated by the muscles to the tool handle. We must control the limits of this “flexibility” if we are to make a straight cut. We can do this by making of ourselves a “machine.” It’s almost as easy as the “tricky part” of the Big Fig Newton dance.
How to do this? Let’s take it step by step. First, grip the saw firmly but not too firmly. The old swordmaster’s instructions apply: Hold the handle like a small bird: Too loose and it will fly away; Too tight and the little bird will be crushed. This grip is important because if you hold either sword or saw too tightly, your muscles and tendons will lock up and you will be unable to form the consistent machine necessary to accurately control the tool’s movement.
The second point to understand about grip is that, while all of the fingers of the hand may touch the saw’s handle, apply your gripping force through the index finger and thumb only (in the case of straight-handled Japanese saws), such that the saw can almost freely pivot around a line drawn between these two fingers and through the handle.
Next we need to align the sawplate with the cut. To do this, arrange the workpiece securely, and assume a relaxed stance facing the layout line you will be cutting to on the workpiece with eyeball centered on the layout line. Then, with saw held in the relaxed swordsman’s grip you intend to use during the cut, hang it loosely down alongside your leg. Stand back from the line and adjust your stance so the plate of the hanging saw is in the same plane as the the intended cut line, but when fine tuning your stance (this next part is important) don’t move your hands, arms, shoulders or hips to align the sawblade with the plane of the cut, but rather move your feet. This is approximately the ideal angle between your body and the intended cut.
Next, without changing position, center your dominant eye on this plane again.
Then, being careful to avoid hitting anything (especially stray bench dogs or kitties), gently but freely swing the saw forward and back 90˚inside this same plane. If your hand or your saw touches your leg, or your elbow hits your side, then adjust your stance so they don’t. The saw must swing freely with the sawblade in the same plane as the cut, with your shoulder joint, elbow, wrist and eye all centered in the same vertical plane.
Next, swing the saw up into the cutting position, and move it back and forth as if cutting wood. Your grip should still be loose (remember the little bird), and the saw should continue to move in an invisible plane centered through your shoulder, elbow, wrist, sawblade, and the layout line. Now pay close attention to the movement of your hand as it goes forward and back; Is it still traveling a little right and left in a horizontal arc? It probably is, my cyborg friend.
Now, while maintaining the stance established earlier, step forward enough to actually make a test cut. Start with a few itsy bitsy teeny weeny little cuts in a test piece to establish a stable beginning for the kerf. Then begin cutting in earnest, but while doing so, pay attention to the movement of your hand. Is it still scribing right and left horizontal arcs in the air? If it is, then on the cutting stroke, in the case of a Japanese pull saw, or the return stroke in the case of a Western push saw, reposition your stance so the inside of your elbow lightly brushes your side. Then adjust your head and eye to match. This contact between elbow and side is an important target point that will help position one end of each stroke, essentially creating rails for the machine to operate within. Remember the feeling of this contact.
When you make the cut, you will notice the sawblade is still scribing small arcs right or left. This fine movement persists because the wrist joint is too stiff preventing it from rotating slightly to keep the sawblade moving in a straight line, with the result that the saw’s handle is either rotating too much or too little, too soon or too late, causing the sawblade to deviate from the plane of the cut. It is impossible to reduce this out-of-plane deviation to zero, but you can cancel out most of it by maintaining your swordsman’s grip, loosening your wrist and actively rotating it in anticipation of this right-left arc. Yes, you can do it.
Your shoulder, elbow, flexible wrist and hand, supported by the rest of your stone-stable body, and watched over by your unrelenting Sauron-like eye, now form a machine with invisible rails that will move the saw in a vertical plane almost perfectly aligned with the plane of the line to be cut (perfection is unattainable and unnecessary).
One last point. It is essential to realize that the saw cuts because it is sharp and wants to make sawdust, not because of thy mighty arm, Oh Lord Cyborg. This is another phrase worthy of a forehead tattoo if you have any room left (ツ)。When we actively apply much force to a saw, especially if the teeth are dull, it will resist our boorish behavior, stumble over the woodgrain, clog with the sawdust, and almost always wander out of the plane we want to cut in. To avoid giving offense, please ensure your saw has a true plate and sharp teeth, do your layout, make the machine, start the cut, then get out of the saw’s way, dammit, and patiently and carefully watch it make sawdust. Don’t be too proud, Lord Cyborg, because, after all, you are the weak link.
Making the machine takes practice and time, but once you have figured it out, and know how it should feel, you will develop muscle memory. It’s like driving a car: Every modern car is different, but every modern car is the same.
BTW, there are various saw jigs one can make and use to enhance one’s cybernetic capabilities which we will consider in future articles.
Pay Attention
Until the necessary muscle memory has permeated all the way to your bones, don’t forget to pay attention to every single stroke you make with your saw. This is exactly the opposite of human nature that wants to keep on cutting like a honey badger going after the fixins for a barbecue ground squirrel sandwich until the cut is finished. But when training oneself to make highly precise sawcuts, it is best to concentrate on each stroke, making sure it doesn’t wander. After all, it is the accumulation of many accurate small cuts that results in an accurate final cut. Likewise, it only takes a few inaccurate cuts to result in a sloppy final cut, so please pay attention.
Once you have become the machine and developed the necessary muscle memory the process will go very quickly indeed. Sadly, this fine muscle memory is not a permanent thing, but once learned it can be quickly remembered.
Stop & Correct
While sawing away, if you notice your cuts are going astray, stop and figure out why. Is your position good? Is your eyeball where it should be? Is the sawblade aligned with the plane of the cut? Is tension released from your wrist? Is your elbow brushing the same place on your side with each stroke? Is the machine operating faithfully or are the invisible rails bent? Are the teeth dull? Are you applying too much pressure? If things aren’t right, stop the cut, figure out why, and make corrections NOW. Don’t wait.
This self-control is possibly the most difficult task in making accurate cuts with a handsaw, but also the most critical to gaining skill. Failure to do it will result in either learning bad habits, or in delays in correcting the ones you already have. BTW, everyone has bad habits they need to work on, including YMHOS.
The Essential Oilpot
Unlike quadruple-distilled, aged in ancient bog-oak unicorn wewe, wood is not a friction-less material. To make things worse, a saw kerf usually becomes “hairy” with loose wood fibers sticking out into the kerf increasing friction in unpredictable ways. And the cherry on top is sap and resin residue found in all wood and which increases friction further.
This friction not only heats the sawblade, possibly warping it and wasting our energy and time, but more importantly it makes it more difficult to control the sawblade in the cut, often making our precision suck big donkey donuts. How to counteract this friction? The classical Japanese solution is the Oilpot.
This tool has long had counterparts throughout the world, and it’s as valuable now as it was six thousand years ago. If you want to use handsaws with high precision, you need to make yourself one. You will be impressed with the difference. Nuff said.
The Two-handed Pistol Grip
When I was a young carpenter working commercial construction, I had a foreman named (I kid thee not) Jack Frost who was offended that God did not give him a tail, especially when working on high scaffolding. Gentle Reader may agree that a fifth appendage could often be handy, despite the fashion compromises it would “entail.” However, consistent with human physical limitations, the fact remains that most joinery saws are operated using either one hand or two, but not by tails.
The discussion above is relevant to all saw grips, but is focused mostly on the single-handed grip. However, just to be thorough, your humble servant would like to describe another style of grip used by some Japanese craftsmen, one your humble servant calls the “Two-handed Pistol Grip.” As the name suggest, instead of gripping the saw in one hand off to the side of the body, the saw’s handle is gripped first by the dominant hand in a pistol grip with the index finger extended along the handle’s side. The index finger of the off-hand is then extended alongside the grip parallel to and opposite that of the dominant hand, and the remaining fingers wrapped over those of the dominant hand.
The sawblade is then operated inside a plane going through the chest and centered on the user’s nose, often quite effectively counteracting the right-left arc tendency. The “swordsman’s grip” is essential to using this technique effectively.
This technique is not good for powerful cuts, but works well for shallow, precise cuts.
I apologize that, despite popular demand, this article lacks clean diagrams and pretty pictures of your humble servant exhibiting these techniques while wearing his sexy blue sequin bikini and famous aluminum-foil alien mind-ray dispersal cap (with curly copper wires and red fringe). But, as the saying goes, “Life is a bowl of cherries, mostly pits.”
Until we meet again, I have the singular honor to remain,
YMHOS
Another construction jobsite possibly non-compliant with OSHA rules.
If you have questions or would like to learn more about our tools, please click the “Pricelist” link here or at the top of the page and use the “Contact Us” form located immediately below.
Please share your insights and comments with everyone in the form located further below labeled “Leave a Reply.” We aren’t evil Google, fascist facebook, or thuggish Twitter and so won’t sell, share, or profitably “misplace” your information. If I lie may all my sawteeth shatter.
I made myself a snowball As perfect as could be. I thought I’d keep it as a pet And let it sleep with me. I made it some pajamas And a pillow for its head. Then last night it ran away, But first it wet the bed.
Shel Silverstein
In this article your humble servant will introduce a Japanese plane called the Kiwaganna, meaning “skewed rabbet plane.”
This is an important handplane in common use in Japan, and one we sell, although it’s not well known in the West. So for the benefit our Beloved Customers, I will explain of some of the solutions learned over the years from senior Japanese craftsmen, and acquired during many decades of brutal study at the University of Stoopid, School of Hard Knocks (Lower Outhouse Campus), which may prove useful.
What is the Kiwaganna Handplane?
The Japanese Kiwaganna is written 際鉋 in Chinese characters, and pronounced kee/wha/gah/nah. “Kiwa” means “edge” or “verge,” and “ganna” means handplane.
While the design of the Japanese version of this handplane is unique, as far as your humble servant is aware many other versions exist around the globe. The Japanese version has a wooden body, a laminated blade, and is significantly lighter in weight and smaller in volume than its counterparts. It is a superior tool, IMHO, but it can be quirky.
This plane can handle a number of tasks, but it specializes in planing a straight-sided groove or rabbet right up to an edge or line with a clean 90˚ inside corner. A few common applications include planing the tongue around the perimeter of a board to make the bottom of a drawer, and raising a panel in frame and panel construction. In construction work it is frequently used to pare and clean tenons in timbers, especially those cut with circular saws which tend to leave a step, and to fit finish woodwork, among many other tasks.
This plane is of course used by joiners, cabinetmakers, sashimonoshi, and furniture makers but you would be surprised at how popular it is with carpenters and timber framers for cleaning the 90˚ inside corners of joints such as tenons.
Craftsmen who use kiwaganna typically own a two-piece set comprised of a right-hand and left-hand version to deal with tight access and changing grain direction. But the right-hand version is the most popular by far.
Advantages of the Kiwaganna Plane
In general, a skewed blade in a rabbet plane provides two benefits. The first is that the reaction forces pushing back on the blade include a vector that tends to push the plane towards the line, edge, inside corner or verge being planed to, making the plane more stable in the cut, an important factor where precision is necessary.
The second and perhaps most important benefit of the skewed blade, however, is the smoother cut and reduced tearout it makes possible, especially important when planing cross-grain.
Another benefit the skewed blade provides in the case of the Japanese kiwaganna is the point of the skewed blade penetrating the body of the plane and ending flush with the side of the body, making possible a zero-clearance cut to a line without the extra weight and cost of complicated mechanisms and reinforcing plates. It’s a deceptively simple but clever design.
Points to Keep In Mind
While a simple tool, the kiwaganna often proves frustrating to first-timers. Indeed, your humble servant struggled with kiwaganna for far too long before he figured them out. To avoid similar damage to brain and ego, Beloved Customers that wish to become proficient in using this elegant tool will find it useful to understand the following nine points. The articles linked to below, while not written specifically about the kiwaganna, are nonetheless relevant and may prove helpful
1. First, a brief inspection of the body and the cuts made to receive the blade will make it clear that kiwaganna dai (body) are more fragile than that of regular hiraganna planes, so when adjusting the blade, please use a wooden, plastic or rawhide mallet, not a steel hammer.
2. When removing the blade, strike the dai at the same angle as the blade is inlet into the dai to reduce unnecessary stresses. This means you will hit the top corner of the dai on the side opposite where the blade’s point exits. Clip off and round over this corner of the dai with a knife or chisel to prevent your mallet from chipping the dai. Striking the opposite corner can have bad results.
3. The first step in truing/adjusting the blade of a kiwaganna plane is to sharpen and polish the blade and uragane (chipbreaker) well, make sure they fit each other tightly without a gap near the cutting edge, and check that there is adequate and uniform clearance at the mouth so that shavings flow smoothly without clogging. The skewed nature of the blade and chipbreaker make this difficult to judge, so exercise caution. In many cases, the plane will work just fine, and maybe even better, without its uragane. The uragane has a bevel ground into its pointy corner. Make sure this is not touching the dai when inserted properly. Keep in mind that you will need to periodically grind this bevel down after sharpening the blade every few times or it will touch the dai creating a restriction where shavings will become jammed. When you sharpen the blade, you will also need to resharpen the uragane too to ensure they match each other tightly. Not every time, but once in a while. A lot of people fail to maintain the uragane and then suffer emotional anguish when their plane mysteriously stops working. Mystery solved.
4. The right and left side edges of the blade must fit the retention grooves tightly where they exit the top surface of the dai. If the fit is too loose, the blade will be difficult to keep in alignment, but if the fit is too tight the blade may crack the dai during seasonal shrinkage. Older dai are usually safe, but a plane shipped from a wet Tokyo summer to a hellishly dry Arizona may experience problems. This articleprovides more details about fitting the body to the blade.
If it becomes necessary to shave the grooves, work very slowly and carefully. Color the blade’s side edges with pencil lead, marking pen ink or Dykem. Insert it into the grooves and note the high colored areas. Shave these down just a tiny tiny bit with a very sharp chisel, or a metal file, then insert the blade and check. Repeat as necessary. Don’t create a big gap between the walls of the groove and the sides of the blade (versus face and underside of the blade which must be tightly pinched in the grooves), just make sure the width of the blade is not wedged tightly between the grooves.
5. Check that the “ear” of the blade (the chamfered corner at the cutting edge opposite the pointy corner) is ground back enough so it does not terminate inside the groove, because if it does, shavings will become jammed. Don’t forget that, with each sharpening, the sharp portion of the blade will become a little wider and this chamfer a little smaller. If it becomes too small, shavings will become jammed between the blade and retention groove, I promise you, so please grind this chamfer back after every few sharpenings.
6. Here is wisdom: Contact between the back of the blade and the block should not be too high-pressure, otherwise the area on the sole behind the mouth may be pushed out making the plane misbehave, an extremely common problem with this plane. You want uniform pressure where possible to ensure the blade is stable, but remember that it is the grooves pinching the blade that keep it in place, not pressure on its back. This is important: If you find your plane stops cutting, it may be because the portion of the dai at the sole behind the mouth is being pushed out as the blade becomes shorter/thicker. The surest way to check this is to use a notched straightedge like the 400mm Matsui Precision product we carry. If the sole behind the mouth is pushed out such that it contacts the straightedge, use a scraper or whatever to pare/shave/scrape excess material away. Indeed, a gap at this area is better than contact. As the blade becomes gradually shorter after much use, its wedging action on the dai may increase pushing the sole behind the mouth out, lifting the cutting edge away from the surface of the wood you need to plane thereby preventing it from cutting consistently, if at all, so check for proper clearance occasionally.
7. With the blade fitted to the grooves and most of the pressure relieved from its back, insert the blade. Check that it projects evenly from the mouth its full width. This is very important. If it projects further on one side than the other, resharpen/reshape the cutting edge so it projects perfectly uniformly. Uneven projection is almost always the result of the user unintentionally and gradually changing the angle of the skew over multiple sharpening sessions, and it always causes problems. Besides projecting uniformly from the mouth (when the sole is at the mouth is perfectly flat), the point of the blade must penetrate the dai (body) and be flush with the outside surface of the sidewall. Heed these words: Failure to get these two subtle details right is the most common cause of failure to perform in the Kiwaganna plane.
8. The mouth opening, in other words the gap between the blade and the sole of the dai where it exits the dai, must be narrow, and even in width, but not closed or skewed, otherwise shavings will jamb in the mouth, another common problem with kiwaganna. If the mouth is not even, use an adjustable steel protractor to match the angle of the blade measured from the side of the dai where the point of the blade exits. Remove the blade and mark the mouth with a sharp marking knife so the mouth is exactly the same angle as the blade. When doing this layout, be extremely careful to make the mouth opening of uniform width to match the cutting edge, but keep the mouth as narrow as possible. Use a sharp chisel to cut to this line making the mouth perfectly uniform. Insert a thin knife blade (or sharpened utility knife blade) into the mouth to shave and clean it after chiseling.
9. There is nothing wrong with leaving the sole perfectly flat instead of having the hollowed-out areas typically added to standard hiraganna planes. Just make sure it is truly perfectly flat. I have no problem with using sandpaper on float glass to true the sole of a kiwaganna, but a card scraper is a better tool for the job.
Juggling Blades
Although we addressed them above, let’s review the two critical factors you must juggle to keep a kiwaganna working well. I’m repeating these points not because I doubt Beloved Customer’s intelligence, but only because repetition improves understanding.
First, maintain the angle of the blade’s skew so that it projects a uniform distance from the mouth (with the mouth/sole flat and true). To do this you must pay more attention when sharpening the blade than is normally necessary. If you get this wrong, nothing will go right.
Second, as mentioned above, to cut into the corner of the rabbet cleanly, the point of the sharpened blade must penetrate the sidewall of the dai and be perfectly flush with the sidewall but without projecting out past the sidewall when the blade is projecting the right amount from the mouth and uniformly across its width. If the skew of the blade is wrong, or the dai is warped or worn, this point will end up being either recessed inside the sidewall or projecting outside it. It needs to be flush with the sidewall. If it is not, you may need to either shave material from the side of the plane (not recommended) or grind down the side edge of the blade near the point, a drastic measure. This is seldom necessary, and when it is, the reason is almost always a badly warped dai.
As you can see, this is a juggling act, but so long as you focus on these two points, and maintain the proper skew angle, all the blades will remain gleefully spinning in the air as you grin from ear to ear.
If you have questions or would like to learn more about our tools, please click the “Pricelist” link here or at the top of the page and use the “Contact Us” form located immediately below.
Please share your insights and comments with everyone in the form located further below labeled “Leave a Reply.” We aren’t evil Google, fascist facebook, thuggish Twitter or a US government IT consultant and so won’t sell, share, or profitably “misplace” your information. If I lie may my kiwaganna planes all warp to resemble mushy bananas.
In this article your humble servant will introduce a standard woodworking tool which I believe to be unique to Japan, although I have no doubt individual craftsmen around the world have produced versions of it for their own use for hundreds, maybe thousands, of years.
I will explain the jobs this tool is used for, how it is used, how to fettle it, and how to sharpen it. I will also share some first-hand business insight regarding why Japanese women make this tool essential to the joiner in both performing traditional joinery in Japan, as well as the sometimes challenging task of getting paid for his work.
Mr. Spock will also make a brief contribution to the discussion.
Definition & Pronunciation
The Sokozarai Nomi (pronounced Soh/koh/zah/rahi noh/me and written 底浚い鑿 ) translates to “bottom-cleaning chisel.”
It is a simple tool consisting of a differentially-hardened steel shaft, with a small, short, sharp foot formed at the end, attached via a tang to a wooden handle, and secured by a conical ferrule.
The Sokozarai chisel is one of three specialized chisels used specifically for joinery work. Cabinetmakers and furniture makers use it too. Two other specialty joiner chisels are the “Mori Nomi,” which translates to “harpoon chisel,” and “Kama nomi,” which translates to “sickle chisel.” Perhaps we will discuss these in a future article.
A larger version of the sokozarai chisel is used for cleaning the bottom of the larger mortises commonly cut in timber frames.
The Role of the Sokozarai Chisel
The sokozarai chisel is used for two purposes. The first is loosening and removing chips from inside mortises. One simply hooks the offending waste with the chisel’s toe and flips it out.
The second role of the sokozarai chisel is to flatten and even plane mortise bottoms. When set up correctly, it will cut shavings from the bottom of mortises cut in softwood planing them flat and clean.
Indeed, in advanced joinery work, a skillful joiner will plan and execute his joints such that the material left remaining at the bottom of a mortise cut into a stile intended to receive the tenon from a rail is less than 1mm thick, thin enough to allow light to pass through. The ability to routinely cut joints like this, without cutting all the way through, is a mandatory skill of the professional joiner.
I suspect that about now Gentle Reader is forming his elegant eyebrow into an artistic and skeptical arc as he ponders why one would go to the trouble of making clean and pretty the bottom of a hole upon which no one will ever gaze, leaving a paper-thin wall of uniform thickness at the bottom admitting light into a space no one will ever see. Can there possibly be method to this madness? Welcome to traditional Japanese joinery.
Consider that a rough, bumpy floor in a mortise prevents the tenon from seating the last few millimeters, but by planing it flat with a sokozarai chisel, those last few millimeters can be converted to useful space to house maximum-length tenons ensuring maximum resistance to withdrawal and bending forces resulting in strong, slender but durable joinery without adding extra weight. This is a big deal in the case of the slim, flexible frame members found in operable traditional Japanese joinery such as shoji, itado and tsuitate screens, joinery that must satisfy the severe eye and meet the high standards of fit and finish expected by many Japanese women, the most unforgiving consumers in the world.
I don’t know when this detail entered common use, but as Gentle Reader is no doubt aware, the older and more common type of mortise and tenon joint found in joinery worldwide is the through single or double tenon with the tenon’s end exposed at the rail where it is often wedged, a technique that is undoubtedly stronger.
On the other hand, the fully-housed tenon made easier to fabricate using the sokozarai chisel has two advantages over its older, less-refined brother the through-wedged tenon. First, it simply looks better and more elegant when new, and is therefore better able to survive the strict final inspection by the lady of the house thereby more reliably earning the reward of final payment. Hallelujah, pass the bottle brother!
Second, it simply looks better to the eye and feels better in the hand as time goes by because, as the stile shrinks during drier months, the once flush end of the through-tenon won’t project past the surface of the stile creating an unslightly, uncomfortable bump, and during the wetter months it won’t recede back into the mortise leaving an indentation in the stile and an uneven appearance.
These details are not based on esoteric imaginings about quality, but are make or break business decisions essential to avoiding complaints from the same unforgiving Japanese women. And of course, in a country where advertising and representations are routinely and intentionally false (sad but true), word of mouth among sharp-eyed quick-tongued women is critical to a craftsman’s success. Please note that I say this as someone who has has been married to a Japanese woman for 45 years, has lived and worked in Japan for over 32 years, and during those years has had plenty of direct commercial experience working with Japanese women as both customers and team members.
Next time we are sharing a cup of hot cocoa around the evening fire, remind me to tell you the story about two stressful days spent inspecting Thassos marble slabs for a new building’s lobby walls in the company of three Japanese women: an Architect, a Quantity Surveyor, and a Project Manager. All the story lacks is a Rabbi and a Priest to make a gut-splitting joke (ツ)。
A 4.5mm differentially-hardened sokozarai chisel with red oak handle
Using the Sokozarai Chisel
To use the Sokozarai chisel, and assuming you are right-handed, hold the handle in a fist in your right hand with the blade projecting from the bottom of the fist. Lay the back of the fingers of your left hand on top of and crosswise to the long direction of the mortise. Insert the blade of the chisel into the previously cut mortise hole and press the back of the blade’s neck (opposite the cutting edge of the foot) against the outside edge of your forefinger. Then pinch the blade’s neck between your thumb and forefinger. This is the grip.
To remove loose waste, insert the sokozarai chisel into the mortise hole and move it around gathering chips on the chisel’s toe. Then pull the chisel up and out of the mortise quickly to pop chips out.
To cut loose chips still attached in the mortise hole, press the chisel’s foot to the bottom, move it forward until it snags on irregularities, then rotate the handle towards your body using the forefinger of your left hand as a fulcrum to lever waste out.
To shave the bottom, simply move both hands forward with the bottom of the foot parallel with the intended bottom of the mortise. Developing a sense of the chisel’s action will take practice. Shining a flashlight into the mortise frequently at first will help develop these senses.
To check the depth of the mortise, a specialist kamakebiki, essentially a small router plane, is ideal. But you can make a simple depth gauge by sharpening the edges of the head of a nail or drywall screw, driving or screwing it into a small block of wood, then cutting off and filing the point to avoid ouchies. Using this, you will be able to detect bumps and irregularities remaining on the bottom. Indeed, it too can be used to shave the bottom, but it won’t clean all the way into corners unless you grind the head square or rectangular.
For advanced work, make a slightly undersized test stub tenon with shoulders from hardwood the depth of the finished mortise, and anoint the end with cheap dark lipstick or Vaseline with black oil pigment mixed in. High spots remaining at the bottom of the mortise will be highlighted. With practice, you won’t need this test tenon, but you will still definitely need a sokozarai that is sharp enough to plane the bottom.
Next, let’s consider how to prepare a new sokozarai chisel.
Fettling the Sokozarai Chisel
Unlike most other Japanese chisels, the Sokozari chisel is not laminated construction, but is formed of one piece of differentially-hardened high-carbon steel. Differentially-hardened in this case means that the foot and lower 1/4 of the leg’s length are hardest, becoming progressively softer going up the leg until it is dead soft at the tang. This means the cutting blade, (what your humble servant calls the “foot”) of this chisel will become sharp and stay sharp, but the neck is left softer so it will not snap off, and can even be bent a little to adjust the angle of the foot if necessary.
Low-quality sokozarai have both soft shafts and feet.
Flatten and Polish the Foot’s Bottom
The bottom of the foot needs to be flat and polished, but because of this surface’s narrow width and short length, it can be challenging to accomplish without rounding it over or skewing it.
It often helps to grind a hollow into the foot’s bottom the thickness of a nat’s eyebrow to help speed up the flattening and polishing process. If you use a grinder, be very careful to avoid overheating. It should take no more than one or two brief touches to the wheel.
When flattening and polishing the foot’s bottom surface on diamond plates and stones, it also helps to make a guide block. Cut a slot in the side of a small block of hardwood to house the bent shaft with the bottom of the foot located flush with the block’s bottom surface. Lock the shaft into the guide block with a wedge or a clamp to stabilize it.
The jig in the photos above was made by a Most Beloved Customer who does exceptional high-quality joinery work.
An alternate sharpening jig can made by cutting a crosswise groove, similar to the one shown in the photo below, into the top surface of a stick of scrap wood, perhaps 50mm wide, 200mm long and 20mm thick. The bottom surface of the foot should be almost, but not quite flush with the stick’s edge, projecting the thickness of a piece of paper. Secure this jig to your workbench with a clamp or in a vise, press down on the blade with one hand, and move a sharpening stone along the side of the jig over the foot.
This guide block rides directly on the stone as you flatten and polish the foot’s bottom. Don’t let the foot’s bottom get skewed or rounded over. Work slowly and check constantly. This is a one-time operation.
Once the bottom is flat and polished, you should only need to polish the bottom of the foot on your finishing stone.
Adjust and Polish the Cutting Edge’s Bevel
The bottom of the foot is now flat and pretty, but the angle of the cutting edge is usually still far too steep, and the bevel’s surface is rough. This must be corrected.
Modify the cutting edge’s angle by grinding the bevel on a diamond plate. The final angle you chose for the cutting edge will depend on your preferences and the wood you will be cutting. Steeper angles are more durable. Shallower angles cut better, but dull quicker. 20~24 degrees is usually OK. When I was a young man, I knew professionals who took the bevel angle down to 15 degrees.
You may want to make another narrower guide-block clamping 90 degrees across the the shaft to help hold/stabilize the blade during this operation. When you have adjusted the angle to where you want it to be, then polish it on your sharpening stones. Be careful to avoid skewing it or rounding it over. You want sharp, clean corners.
To routinely sharpen/polish the bevel, hold the chisel in one hand with the bevel face-down on the long side of your sharpening stone. While stabilizing the blade and applying pressure on the bottom of the foot with a fingertip, move the sokozarai chisel back and forth in small strokes being careful to avoid rocking it and rounding it over.
Adjust the Foot’s Length
This step is unnecessary for most applications, but I will touch on it just to be thorough.
The length of the foot is fine as-is for most furniture mortises, but for very tiny mortises as in screens, light fixtures, and small casework, the foot may need to be made shorter. It is not unusual for a tategushi or sashimonoshi to own multiple sokozarai nomi with feet and shafts of different widths and lengths and bevel angles to clean the mortises he makes the most.
Please note that the mortise holes for kumiko members installed in shoji screen and most other types of latticework are shallow and do not require the strength of long tenons, so the mortises are usually cut using mori nomi (harpoon chisels) with a hook on the end to pull out waste quickly, and the bottoms are left rougher.
Conclusion
Beloved Customers that have purchased our chisels, and diligent Gentle Readers that have read this blog, are aware that your humble servant insists our chisels not be used to scrape or lever waste out of joints. The reasons for this are my desire for Beloved Customer’s most excellent chisels to remain as sharp as possible as long as possible, and to avoid chipping the cutting edge. They are, after all, refined cutting tools with sensitive feelings, neither thuggish prybars nor pot-metal screwdrivers.
The Sokozarai chisel was invented specifically as a partner to chisels used for cutting the clean mortises essential to Japanese joinery, and to protect the super-sharp cutting edges of those chisels from damage resulting from barbaric treatment. I encourage you to level-up your joinery skills by procuring and using one. You will be glad you did.
And so I wave farewell until the evening we share a cup of hot cocoa around the irori fire. In the meantime, I am humbly grateful for the honor to remain,
YMHOS
Adieu for now, Gentle Reader!
If you have questions or would like to learn more about our tools, please click the “Pricelist” link here or at the top of the page and use the “Contact Us” form located immediately below.
Please share your insights and comments with everyone by using the form located further below labeled “Leave a Reply.” We aren’t evil Google, fascist facebook, or thuggish Twitter and so won’t sell, share, or profitably “misplace” your information. If I lie may my sokozarai chisels get athletes feet!
A 70mm handplane with a blade by Nakano-san and body by Inomoto-san with a London Finish applied by YMHOS
A person who never made a mistake never tried anything new.
Albert Einstein
here are more ways to finish wood than there are to cook beans, but unlike the musical fruit, the fragrant finishing technique that is the subject of this article became famous through the products of London’s elite gunsmiths such as Durs Egg (Est. 1772), John Rigby & Co (Est, in Dublin in 1775 and moved to London in 1866), Joseph Manton (1766 – 1835), Boss & Co (Est. 1812), James Purdey & Sons (Est. 1814), Holland & Holland (Est. 1835), and a hundred other European gunmakers. However, the technique actually pre-dates the 1700’s by many centuries.
The Traditional London Finish
While the traditional London Finish got its name from the justifiably-famous products of the high-end London gunmakers, some of the most famous of which are named above, since ancient times this technique used to seal and finish high-quality woodwork employed linseed oil, the squeezings from the seeds of a stringy plant called flax.
The difference between the linseed oil widely used for paint production and woodworking and the flax seed oil sold as a health product in the West nowadays is simply the method used to extract the oil from the flax plant.
Of course, Gentle Reader is no doubt aware that the fibers of the cotton plant have been used to make textiles since at least 6,000 BC, but what you may not realize is that it was rare and so labor intensive to produce that at times cotton fabrics cost more than silk in the West, as recorded in tax records of the time. Indeed, it wasn’t until the invention of the Cotton Gin in 1793 that cotton textiles became affordable for ordinary people. My point is that linen cloth made from the fiber of the flax plant, and spun cloth made from animal hair, such as wool, goat and camel, were the most common textiles available probably since Methuselah wore goatskin nappies.
Indeed, flax can be grown in even poor soil, and can be spun and woven into useable thread and cloth in small lots in most any home, so “homespun linen” was once the cheapest most widely-used textile available worldwide, used for everything cotton, polyester, rayon and silk is nowadays, and linseed oil was an ordinary but economically-important by-product of flax production.
The London Finish made famous by the gunsmiths of Olde Londinium consisted of many coats of boiled linseed oil, betimes with some added dryers, forcefully rubbed into the wood by hand (the warm, bare hand, as a matter of fact), allowing days and weeks between coats for the oil to partially polymerize. Indeed, this manual application technique is the source of the term “hand-rubbed finish” that furniture and cabinet companies everywhere lie about applying in our time. If you have a free month, please give it a try.
This finish was also used for furniture and cabinetry since ancient times as referenced in texts of the era which is probably why some modern woodworkers, ignorant of chemistry and eager to employ historical techniques, still soak their projects in linseed oil potions.
While the final product of the traditional London Finish is indeed subtly beautiful, it takes a long time to accomplish, it’s expensive, it does little to prevent moisture from moving in and out of the wood (and therefore allows the wood to rapidly expand and contract with varying moisture content), and it does little to protect the wood from damage. Other downsides include the fact that linseed oil gives a yellow cast to wood, which gunstock makers and other woodworkers historically compensated for by dying the wood slightly red using alcanet root.
Also, linseed oil never fully solidifies and so attracts grime, eventually oxidizing and turning black forming a “patina” many people admire without realizing its dirty nature.
The Modern London Finish
The wood finishing technique described in this article is a modern, improved version of the traditional London Finish, one developed by American custom gunstock makers looking to replicate the beauty of the antique London Finish while providing better durability and moisture resistance for their customer’s expensive firearms and eliminating the expensive and time consuming work of rubbing in stinky, yellowing, dirt-magnet, spontaneously combusting linseed oil.
I learned about it when I was looking for a better finish for the stocks I made for my own smokepoles, everything from flintlock rifles and pistols to large-caliber bolt-action rifles. Through applying, using in the field, and comparing the long-term results of both the traditional linseed oil London Finish and this modern version, I came to treasure the modern version’s subtle beauty, durability and effectiveness at moisture control. Soon I was using it for everything from tool handles to furniture and casework with excellent results.
The primary difference between the traditional and modern versions of the London Finish is that the traditional technique relies heavily on boiled linseed oil, a product that does little to protect wood, while the modern technique relies on modern varnish or polyurethane resins, but with a twist.
Where the two finishes are alike is that neither are surface finishes, but are soaked into the wood’s fibers. By contrast, normally-applied varnish or PU finishes are film finishes that, while they may adhere to the wood well when fresh, do not penetrate deeply, but remain on the surface where they quickly degrade due to UV light exposure, and the stress cracks resulting from expansion and contraction of the wood. Eventually and unavoidably their bond with the wood they are tasked to protect or beautify always fails, usually sooner than later, whereupon it stops doing its job.
The modern London Finish is not a surface film but soaks into the wood’s fibers where it hardens, and is protected from UV and shrinkage damage. It also fills the wood’s pores sealing them long-term and forming a smooth, flat surface free of the dents and streaks at the wood pores that always develop when shrinkable varnish or PU are applied as a surface finish.
Most importantly, it seals the wood with a durable material that cannot be removed without actually carving or abrading the wood away, protecting it from moisture/dirt/oil intrusion. This makes it a better and more attractive long-term finishing solution, one that, unlike the traditional London Finish, doesn’t need to be refreshed annually (yes indeed, annually).
Next, allow your humble servant to present the performance criteria I consider important when selecting a wood finish for tools.
Performance Criteria
The following criteria are focused on improving the longevity, durability and stability of the wooden components of handtools used in woodworking. These include the wooden bodies of handplanes, and the wooden handles of chisels, axes, hammers and gennou.
So what do we need a finish used in these applications to accomplish?
Stability: Minimize moisture movement into and out of the wood cells due to humidity changes, perspiration and rain thereby reducing the swelling, shrinking and warpage of the wood. This is specially important for handplanes, gennou handles, and some types of furniture and cabinetry. A surface finish that quickly oxidizes, suffers UV degradation, becomes inflexible and suffers shrinkage cracks or is easily chipped and/or abraded won’t get the job done for long.
Protection from oil and dirt: Prevent dirt, dust and oil from the user’s hands or the environment from penetrating below the wood’s surface keeping it cleaner. To accomplish this a finish must both fill the ends of open cells exposed at the surface with a water-proof, non-shrink plug (a “filler”) and seal the cells with a waterproof and oil-resistant chemical binder.
Insect and Bacteria Protection: The finish must lock away the yummy smell of raw wood so bugs will go beetling on by without stopping to snack, set up house, or lay eggs. It must also prevent bacteria spores, nasty things always present in dirt, from taking root.
Appearance: A smooth surface that looks like wood, not plastic or varnish.
These are only your humble servant’s criteria, of course; Your needs and expectations may vary.
Why Is the Expansion, Contraction and Stability of a Wooden Tool Component a Concern?
Trees are water pumps. Evaporation at the leaves sucks water, and with it, dissolved chemicals up from the ground. After a tree dies, most of the water contained in its cells migrates out of the wood, the individual cells shrink in size and crinkle as they dry, and the cell walls become stiffer and much stronger. However, despite its transition from a flexible, moist, growing plant to a stiff, dry board, left as-is a dead wood cell does not abandon its God-appointed duty to pump water but will faithfully continue to absorb and expel water, albeit to a more limited degree than when it was alive and kicking, causing its dimensions to shrink and swell in response to changing moisture conditions in the surrounding environment.
The problem is that the rate water enters or leaves the wood cells varies with a number of factors. One such factor is the location of the cell within the block of wood, producing differential expansion/shrinkage along with stresses and warpage. Most importantly, end grain absorbs and releases moisture much more quickly than side/face grain does. Slowing down the rate of water gain/loss is important to minimize and equalize internal stresses and to keep a wood product stable.
Besides the natural seasonal changes in humidity, modern air conditioning and heating equipment can create wild swings in ambient humidity, causing wooden components of furniture and tools, such as the bodies of Japanese handplanes, to warp, harming their ability to plane wood as intended. When this happens, and it will, time and effort is periodically required to adjust a wooden-bodied plane’s sole. This can be frustrating. Short of using a vacuum pump to suck heavy hardening resins into a board’s cells, it is nigh impossible to entirely prevent moisture from entering and leaving wood with changes in environmental humidity, and the dimensional changes, internal stresses, and warping that results.
In the case of a wooden-bodied plane, both ends and the surfaces inside the hole cut to receive the blade have exposed endgrain which absorbs and releases moisture quicker than side grain, so that when the humidity of the surrounding air increases, airborne water penetrates the endgrain faster than the sidegrain, and the endgrain surface at the body’s ends and inside the mouth swell first, causing dimensional changes and differential stresses, and often, warping.
By reducing the rate of absorption of moisture by the endgrain fibers to more closely match that of sidegrain fibers, swelling, shrinking and warping can be reduced. This is where the London Finish shines.
Since learning this method, I have used it not only on my guns, but also on timber frames, doors, tools, workbenches, furniture, cabinets, chests, tansu, tsuitate, and other wood products with excellent results.
Danish Oil
A note about so-called “Danish Oil” finishes is called for at this point. Danish Oil is boiled linseed oil combined with thinners, dryers, and resins. It polymerizes much quicker than simple boiled linseed oil, and is much easier to apply. By itself, varnishes and polyurethanes will not soak far into the pores of the wood (xylem tracheid), but by reducing its viscosity with linseed oil and thinner, the liquid will soak further into the grain and pores before more-or-less hardening. While superior to plain BLO (boiled linseed oil), Danish Oil is still not effective at either preventing water migration, or protecting the wood from dirt and oils. And besides, it changes the color of the wood to which it is applied, it stinks and it starts fires. Nothing good.
A gennou hammer with a Kosaburo head and black persimmon handle with a London Finish
Applying the Modern London Finish
This technique requires only a few inexpensive tools and materials, and no equipment of any kind, but it does take some time and effort to apply.
Tools and Supplies
You will need the following tools and supplies:
Clear varnish or polyurethane finish in a can. Gloss finish is fine, but I prefer a satin finish. Minwax PU works well, while Epifanes is the best I have experience using.
Thinner or mineral spirits. Not the water/acetone/oil-based low-VOC toilet cleaner sold at home centers. A professional-grade thinner from a Sherwin Williams store or other specialist paint store selling professional-grade materials is best.
Mixing container the size of a soup can or jam jar with a lid.
Small paintbrush, perhaps 3/4″ wide. Cheap is fine.
320 grit and 600 grit wet-or-dry sandpaper.
Clean rags,
Brown paper from shopping bags
Latex/rubber gloves to keep finish mixture off hands. It can get messy.
Masking tape.
The Finish Mixture
The finish mixture to be used is the varnish or PU you selected thinned 100% with thinner. You won’t need much to complete a few plane bodies or tool handles, less than half a soup can in fact, and it’s best to use in small batches. The lid will keep it from hardening between sessions. It’s not a lot of work, but with drying time, the process may take five or six days.
The Steps in Finishing a Wooden Handplane Body or Tool Handle
1. Remove the blade and chipbreaker. Tape the chipbreaker retention rod with masking tape. In the case of gennou handles, tape the entire head except the wood exposed at the top surface of the eye. For chisel handles, tape the ferrule, crown and the striking end of the handle (you don’t want the finish mixture to soak into the end of the chisel handle because it will make the fibers too brittle.) For paring chisels like usunomi that are not struck with a hammer, soak as much of the mixture into the handle’s end as possible
2. Apply the finish mixture to the end grain at the plane body’s ends and all surfaces inside the mouth. In the case of hammer/gennou handles, apply it most heavily to the butt and eye. Apply it heavily, frequently, and forcefully to encourage the wood to soak up as much as possible. Repeat until the wood won’t soak up more. This is the step that matters most. Apply to all other surface of the dai as well. Allow to dry overnight. There’s absolutely no need to put any effort into making it pretty at this stage.
3. Repeat Step 2.
4. Apply another coat of finish mixture, and while it is still wet, use small pieces of 320WD paper with fingers and sticks to wet-sand all surfaces thoroughly. The goal is to produce a fine slurry of finish mixture and sawdust, and to force this deep into the wood’s grain, especially end-grain, clogging the pores solid. Don’t sand the area in front of the plane body’s mouth hard enough or long enough to remove material, change its shape, or round over the corners, though! This is extremely important. This slurry, combined with the varnish/PU already hardened in the wood’s pores, will serve to drastically slow down moisture movement once it sets. It won’t stop it entirely, but it will moderate it more than spindle oil, linseed oil or Danish oil ever could, and it won’t crack or flake off leaving the wood unprotected. Don’t wipe off the wet slurry, but leave it standing/smeared on the wood’s surface and let it dry overnight. It will look terrible for now, but never fear for tis all part of a cunning plan (ツ)!
5. Apply another coat of finish and wet sand with 320 grit WD paper again making sure to hit all the places you might have missed before and knocking down any hardened slurry from step 4. Allow to dry overnight.
6. Wet sand with the finish mixture using 600 grit WD sandpaper this time. Be sure to sand down and completely and thoroughly remove any hardened finish or slurry remaining on the wood’s surface. This is important. After sanding, but before the mixture hardens, scrub it down with clean rags and/or brown paper from shopping bags to remove all remaining finish from the wood’s surface. Allow to dry overnight. You may need to repeat this step for best results.
7. The next day examine the wood’s surface for any remaining finish/slurry visible on surfaces. Remove any you find with 600 grit WD sandpaper and the mixture.
8. Allow to dry for 24 hours.
9. Scrub with brown paper from a shopping bag.
10. Apply automotive carnuba paste wax, and polish out.
Remember that, if applied correctly, the London Finish as described herein should not create interference or change tolerances in the tool because there shouldn’t be any finish material left proud of any of the tool’s surfaces to cause interference.
When finishing the blade retention grooves, you will find it difficult to sand up inside them with your fingers, so use sticks. But don’t remove much material in creating a slurry or the blade may become too loose. And be sure to remove any and all slurry or finish that remains on the surface.
At this point in the process, the London Finish is complete. It is well suited, in my opinion, for guns, tools, workbenches, doors, timber frames, as well as any furniture or casework where protection is desired but a surface finish is not desired. This finish also works exceptionally well for carved wooden surfaces, but with less sanding. It also has the distinct advantage that it does not require careful application, so if brush hairs or sawdust get caught in the finish, or bubbles or sags develop, never fear, because in accordance with our plan so cunning we could stick a tail on it and call it a weasel, they are all going to be wet-sanded away. If you decide to apply a final surface coat, however, then greater care is necessary for the final coat.
If you are doing casework or need an attractive surface finish, a topcoat or two of the same mixture, freshly made, applied with a clean brush is just the ticket. If a really nice finish is desired, several coats can be applied, wet sanding between each, and finally polishing with polishing compound (automotive paint supply houses carry this in many grits) to create a mirror finish.
If you feel brave enough to tackle large surfaces, such as a tabletop where this finishing technique excels, some time and effort can be saved by using a pneumatic or brushless random orbital sander. The type of motor matters because you don’t want a spark to ignite the thinner when wet sanding. You have been warned.
A quick note on frame and panel construction is warranted at this point. If possible, it is best to apply the finish (any finish for that matter) to all surfaces of panels, especially endgrain, before gluing them into their frames. In any case, a bit of paste wax (I use beeswax-based Briwax) applied to the inside of frame rabbets and the edges of panels before assembly will prevent finish from accidentally gluing the panels into the frames, thereby restricting expansion and contraction, and eventually producing cracked panels.
An 80mm handplane with a blade by Yokosaka-san and body by Koyoshiya with a London Finish. If it looks as if no finish at all has been applied, that’s because there is no film finish on the wood’s surface to be seen.
The Story of Why I Started Using the London Finish for Plane Bodies
Back in 2010 I was transferred from Orange County in Southern California to Tokyo, Japan. Due to an error by the moving company, most of my beloved tools were left behind in a storage unit In Las Vegas, Nevada, placing my sanity at imminent risk. I bought replacement chisels and planes (hiraganna, mentori, shakuri, etc) in Tokyo at that time. I had become dreadfully tired of the warpage that often developed in my plane bodies each time I moved, so I considered ways to reduce this nasty tendency, and of course, tried the London Finish I had been using on my gunstocks back in the USA. The results were perfect.
After applying the London Finish to them in Tokyo, I used them for about a year through all the seasonal humidity changes common to Japan and exposed to indoor heating and cooling. They stayed straight the entire time. My job then transferred me to the Pacific island of Guam, with high temperatures and constant 85% humidity, where I used and stored these high-quality planes in a hot and humid garage for 1.5 years. They still stayed straight. When I returned to Tokyo, my wooden bodied planes again made the 35 day land and sea voyage inside a hot and humid container. They arrived at their new home straight. At the time I am writing this, those same planes have been in my home here in Tokyo for over 8 years through the various seasons and humidity changes, and have mostly remained straight.
Not having to regularly true the soles of my wooden planes since then has saved me a lot of time and headaches (as he is wont, Murphy carefully ensured that they warped and stopped working at the most inconvenient time possible), and of course has extended their useful life.
Another special benefit in my case is the resistance the finish has to sweat, oils, acid and dirt from my hands, which, in my case, causes white oak to turn black almost immediately. This is doubly true in the case of my chisel and hammer handles.
I have taught this method to many people that admired my completed woodworking projects and cabinets and handmade gunstocks, but few have had the patience required to actually attempt it. Of course, being all handwork, and taking quite a bit of time to accomplish, it is not suited to most commercial situations.
As for hobby woodworkers, there seem to be two schools of thought. The first hasn’t the patience to deal with any finish that can’t be applied with either a spraygun or power roller. Most of the woodworking publications energetically promote equipment-intensive commercial production methods even to the amateur, and feverishly foster this attitude. At the the risk of sounding cynical, I ask you Gentle Reader, is owning an airless spray system really necessary to perform quality woodworking, or is such equipment more of a profit center for manufacturers and retailers?
With this statement, I am certain I would receive piles of poisonous complaints from advertisers to this blog (if I had any), and perhaps even threats about pulling said advertisements. Good thing I don’t give a rodent’s ruddy fundament about such things or the feeling of rejection might crush my fragile ego like a raw egg in a little boy’s back pocket (シ)。
At the other extreme, there are devotees of the Neanderthal school that have been indoctrinated by romantic viewpoints in the woodworking press, or influenced by things written in books a hundred years ago. These gentle souls are drawn to archaic finishes such as boiled linseed oil, beeswax, and unicorn piss.
To the production-method advocates I say save production methods for production work, and seek better quality for your handmade projects.
To the Birkinstock-wearing Neanderthals I say, there is a reason old unrestored furniture and gunstocks are dark, grungy, and yes, dirty: Linseed oil and beeswax. Consider what you want your work to look like in 100 years. Certainly not cracked, water-damaged, and dirty. And genuine unicorn tinkle is practically impossible to come by nowadays, anyway, even on Amazon.
I promise you the results will be worthy, with no downside, and your planes, tools handles and wooden projects will not only look better longer, but will be tougher and more stable.
The Abura Dai
I would like to add a note here about a Japanese technique intended to improve the stability of handplane bodies, namely the “Abura Dai 油台” which translates to “Oil Body.”
The idea is to soak the oak body (dai) of a handplane in low-viscosity spindle oil until it takes up a significant amount thereby minimizing moisture exchange and improving the stability of the handplane’s body. Does it work?
I own and use a 65mm abura dai handplane I purchased as a sample around 10 years ago, and which seems to be fairly stable. But I am not a fan of abura dai for two reasons. First, by design spindle oil never dries and is always wet. Therefore, the dai is always a little oily and definitely stinky. I don’t like the smell of spindle oil nor do I want to feel it on my hands unless I’m being paid for it.
Second, it makes the sole of the handplane softer, an area I would prefer remain harder, increasing wear noticeably. I was told about the failings of the abura dai by professional woodworkers many years ago, and the wear on the sole of this 65mm plane confirms their observations.
I encourage Gentle Reader to give the London Finish a try. You will like the results. And please share your impressions with your humble servant and other Gentle Readers.
Until then, I have the honor to remain,
YMHOS
Byodoin Temple on a clear Winter’s day
If you have questions or would like to learn more about our tools, please click the “Pricelist” link here or at the top of the page and use the “Contact Us” form located immediately below.
Please share your insights and comments with everyone by using the form located further below labeled “Leave a Reply.” We aren’t evil Google, fascist facebook, or treacherous TikTok and so won’t sell, share, or profitably “misplace” your information. If I lie may my all my planes warp into pretzels.
Make of yourself an honest man, and there will be one less rascal in the world.
Thomas Carlyle 1803 – 1855
It behooves a man to know human nature in general and his own nature in particular, at least in your humble servant’s opinion, which, along with $1.25, will buy a soft drink in a can.
Has Gentle Reader ever wondered why people do some of the things they do? While it makes perfect sense to work diligently for the necessities of life such as food, clothing, and housing, we do many unnecessary things that yield no apparent profit, for example gardening, despite fruits, vegetables and even flowers being easier and cheaper to purchase in a grocery store. And how about the large, lush green lawns and ornamental plants and trees we install around around our homes and maintain at great effort and expense, plants that serve no practical purpose but cost us time and money and other resources?
What whips drives us to these excesses?
I daresay this isn’t just a guy thing, either. Many ladies insist on weaving, knitting, and sewing clothing and home furnishings by hand even when mass-produced, inexpensive products of similar quality and utility can be readily purchased from stores anywhere. It just doesn’t make sense, and I say that as a husband who, at the behest of She Who Must be Obeyed, has spent thousands of dollars on CNC sewing machines with unobtanium armatures and smoothie attachments all to make quilts that never spend a second on a bed and seldom even see the light of day.
What is this madness that has her gripped in its barbed talons?
But I fear the madness runs deeper still, for many males of the species spend inordinate amounts of time and money buying trucks, ATVs, clothing that makes them look like trees, camping gear and weapons of death and destruction (aka WODADs) in preparation for hunting season, a time when otherwise sane people don orange costumes and chase Bambi around the mountains and forests just to obtain the most expensive meat to be found anywhere in the world. It’s just nuts.
And don’t even get me started about fishing. A good time was had by all during these hunting and fishing expeditions, but the financial benefits are impossible to calculate. It just isn’t logical…
Woodworking is useful for making housing and furniture and many of the tools essential to civilization, but what about woodworking as a hobby? Isn’t it quicker, easier, less expensive and more sliver-free to buy pre-fabricated houses assembled on-site with bolts and furniture made of MDF, plastic and steel excreted by Chinese factories? Of course it is, so what is this friking parasite madly manipulating levers in our brains compelling us to make these things with our own hands instead?!
I don’t know why these urges drive us so relentlessly. I only know we want to do them and that doing them gives us satisfaction. But I do have a humble theory I will present for Gentle Reader’s consideration, just for giggles.
I believe that the habits and actions that successfully preserved our ancestors long enough for them to produce and raise each generation of humans became imprinted in each subsequent generation’s DNA.
Successful farmers who survived in ancient times passed particular genes on to their descendants. I suspect it is the farmer gene that compels so many of us to grow fruits and vegetable and surround our homes and cities with lawns and plants, a form of agriculture similar to that which kept our ancestors from starvation. It’s the only possible explanation for the universal compulsion to plant stuff.
The children of women who spun, wove, knitted and sewed clothing and bedding survived cold winters inheriting the sewing gene. I’m not sure where smoothie attachments fit into the equation, but clearly sewing machines have become part of the compulsion in modern times, possible evidence that behaviors evolve.
The children of successful hunters and fishermen survived too. The compulsion to perform these activities is still strong in many, your humble servant included. I’m sure you’ll agree that the ritual of talking around the evening camp fire about the big one that got away while saber tooth tigers and cave bears prowled in the shadows beyond the light of the communal fire is much much older than recorded history.
Somewhere not far out on a limb of Gentle Reader’s family tree are hundreds, perhaps thousands of ancestors that shaped trees to make houses to protect and keep their families warm, and beds, tables, benches and chests to make life cleaner and more pleasant. This is a healthy and noble urge, one that, like farming, sewing, hunting and fishing has been useful in keeping body and soul in intimate contact for many thousands of generations in humanity’s past.
My father inherited the woodworking gene from a carpenter ancestor, one of two brothers that left England in the 1600’s to travel to South Carolina by leaky boat. It appears I in turn have passed it down to my sons and grandsons. I am glad of this for mayhap I hear the toenails of wolves clicking on stones in the dark shadows outside the firelight just now, so a solid door of thick hewn oak with a sturdy cross-bar may come in handy before the morning.
But for now, please ignore the snuffling and scratching noises at the door, pull up a chair by the fire and let’s get started on that chess game, shall we?
YMHOS
Waiting for dark, and dinner to walk out through that confounded wooden door.
If you have questions or would like to learn more about our tools, please click the see the “Pricelist” link here or at the top of the page and use the “Contact Us” form located immediately below.
Please share your insights and comments with everyone by using the form located further below labeled “Leave a Reply.” We aren’t evil Google, fascist facebook, or thuggish Twitter and so won’t sell, share, or profitably “misplace” your information. If I lie may my riding lawnmower lose power as I pass between two ready-mix concrete trucks on the Tomei Highway. Eeeehah!
By concentrating on precision, one arrives at technique, but by concentrating on technique one does not arrive at precision.
Bruno Walter
As mentioned in the previous post in this series, in Japan the mortise chisel is called the “Joiner’s Chisel,” because it is specifically designed for precisely and quickly cutting the many small mortises craftsmen in the joiners trade use in making doors, windows, shoji, screens, furniture and cabinetry.
Why must it cut mortises quickly? Simply because a few seconds of time wasted on each of many mortises cut during the workday by an uncooperative chisel will quickly add up to hours of lost productivity.
Why must it cut mortises precisely? Simply because defects hidden inside mortises with poor internal tolerances tend to accumulate and too often turn what would otherwise be a well-made piece of furniture or joinery into a rickety old Chinese lawnchair.
In this post we will discuss what to look for in a mortise chisel, and how to correct some typical problems. Most of the concepts discussed in this post are applicable to oiirenomi and atsunomi used for cutting mortises as well, although such chisels lack the same shape advantages.
Klipstein’s Law of Thermodynamics
Just in case Gentle Reader didn’t notice, your humble servant has strong opinions about mortise chisels, partly because I was trained by no-nonsense professionals to routinely cut hundreds of mortises in a single sitting, and partly because bitter experience has taught me the truth that sloppy mortises result in both sloppy products and crushing headaches. Nothing like a bunch of tiny errors when making a series of latticework doors to painfully confirm the validity of Klipstein’s Law of Thermodynamics: “Tolerances inevitably accumulate unidirectionally toward maximum difficulty to assemble.”
Because of this hard-earned experience we have given our blacksmiths specific dimensional tolerance criteria for the mortise chisels they make for us. My hearing isn’t what it once was, so I’m not sure what they are muttering in response to my pointed insistence, but it sounds something like “frikin prissy pink princess expects too much of a damned chisel.”
Your most humble and obedient servant, however, is much too dignified and polite to respond in so many words, but at such times I think they are stubborn old farts that have never used a mortise chisel. In any case, those who use our mortise chisels benefit from the princess impulse in your humble servant.
What to Look For
Mortise chisels are used routinely by only the most skilled craftsmen. Despite their simple appearance, mortise chisels are required to cut to tighter tolerances than other type of chisel, but because our’s are handmade in the traditional manner without the use of CNC machinery, and because perfection is unattainable in mortal endeavors, they are seldom perfect when new, so Beloved Customer should plan on tuning your mortise chisels before doing serious high-volume work.
Indeed, it has long been standard practice among Japanese joiners to modify their chisels and planes to their preferences, and correcting the dimensional imperfections of mortise chisels is at the top of the list, not because they tend to have more imperfections than other chisels, but because more precise work is expected of them.
If you recall some of the mortises you have cut before now you may have noticed that despite your best efforts and forehead-splitting concentration, the sides ended up out-of-square with the workpiece’s top surface, or the side walls were raggedly gouged, or even undercut. While of course unacceptable, these defects are not unusual, and may be due to perfidious pixies, your technique, or perhaps a combination of both, but my money’s on the chisel being the culprit.
If you’re experiencing such problems, please examine your mortise chisel. If it does not meet the ideal standards in the list below (and it won’t), you should make corrections. You’ll be glad you did. There is a link to a document below that illustrates the ideal mortise chisel as well as some typical problems that may prove useful.
The plane formed by the flat lands surrounding the hollow-ground ura depression should be truly flat and without twist over its entire length from cutting edge to shoulder.
The blade’s width should be consistent over its entire length. Alternately, it is acceptable if the blade’s width becomes just slightly and gradually narrower moving from cutting edge to neck. But not too much. On the other hand, a blade that widens towards the neck is an abomination to be avoided like the spotty-bottom footpads at the California Franchise Tax Board.
The blade’s sides should be flat, planar, free of twist, square to the ura, and square to the blade’s top face. Accordingly, a cross-section taken anywhere across the width of the blade should be rectangular anywhere along its length, with all corners 90°. Picky details, but they can make a big difference in the quality of the finished mortise.
The top face (surface where the brand is stamped) need not be planar along its length, but it must be square to the sides (and therefore parallel with the ura) at all points along the blade’s length.
Make no mistake, this is a tall order in a hand-forged tool that has never seen a milling machine, planer, or CNC grinder. Few handmade mortise chisels can meet these standards when new, but these details can make all the difference.
Let’s begin the examination part of this job. You will need a 6~12″ straightedge, a small precision square like the Matsui Precision products we carry, and a precision caliper, whether vernier, dial or digital it matters not.
Record Your Observations
Too often the number of dimensional irregularities that require attention are complicated enough to create confusion. This can result in even experienced people making one irregularity worse, or even generating new problems, while attempting to resolve the initial irregularity, like inadvertently creating more knots while trying to untangle a snarled mess of string.
To avoid confusion, I recommend you make a simple orthogonal hand sketch of your chisel to record irregularities. This sketch should show at least four views of the blade including left and right sides, its face (opposite the hollow-ground ura), and an end view looking towards the cutting edge’s bevel. You may also need to make a few cross-section sketches
Record the results of your examination as annotations and red lines on these sketches to help you plan and execute the work of correcting any problems you may find. There are always a few, and you will need to keep track of each one, and its relationship with the others.
Examine and True the Ura
The first step is to check the ura, the polished lands (flat surfaces) surrounding the hollow-ground depression on the chisel’s back. These must be flat and in the same plane (coplanar). This detail is very important.
A straightedge is good enough for a quick examination, but a more reliable method is to use a granite surface plate. A less expensive and handier option is a simple piece of ⅜” or thicker float glass.
To use a glass surface plate, apply marking pen ink or Dykem to the ura’s lands. Smear a tiny amount of finishing stone mud around on the glass plate. With the entire blade resting on the plate, and finger pressure straight down in the middle of the blade’s face, move it in a oval pattern through the sharpening stone mud. The ink or Dykem at the high spots will be rubbed off, but will remain at the low spots. This will show you where and how much material must be removed to flatten the ura’s lands
Then, true the ura using a diamond plate, diamond stone, sharpening stones, and/or the glass surface plate. This step is not so important in the case of other types of chisels, but a mortise chisel must have a reasonably flat ura. Without a planar ura, the rest of your examination may be inaccurate. The article at this LINK contains a more detailed discussion with pretty pictures.
Do this work carefully, for if you heavy-handedly remove too much steel, the useful life of the chisel will be significantly reduced. Note that this is a one-time operation in the life of most chisels.
Examine the Blade’s Width and Taper
Next, check the width of your mortise chisel measured across the ura using a caliper, micrometer or other reliable gauge. Relative width is what you need to check, not absolute inches or millimeters, unless you expect your chisel to cut precisely-dimensioned mortises, something that is seldom necessary in the real world.
Measure the blade’s width at five or six locations along the cutting edge, in the middle, and near the neck before it narrows. Make a sketch of the blade and annotate these dimensions on it
Use the glass surface plate at this time to check the sides for flatness. The black oxide surface skin will be worn away by the sharpening stone mud marking the high points, but don’t let the change in cosmetic appearance bother you.
Ideally, the blade will be the same width its full length. However, it is usually acceptable for the blade to be slightly wider at the cutting edge than near the shoulder. But if it is wider at the shoulder than the cutting end, it will bind in the cut, tend to split the mortise, and the finished mortise will be skiwampus. This must be remedied by grinding the blade on diamond plates and polishing on sharpening stones.
But don’t do anything yet since there are more details you need to examine first. Just make a note on your little sketch.
Examine the Blade’s Sides
Straight Sides
Use a good straight-edge to check both of the blade’s sides. They must be straight. If they curve in or out it will be difficult to convince it to cut a clean straight mortise. If the blade is banana-shaped, it can’t cut a straight mortise anymore than a politician can tell the truth while his heart beats (it’s rumored that some have hearts).
If the blade’s sides are not straight, they must be corrected by carefully grinding and polishing them. But hold your horses there Hoss, don’t do anything drastic yet, just make a note on your little drawing: there’s still more to check first.
Flat Sides
Next check the sides of the blade across their width. They must be either flat (best) or hollow ground (acceptable). But if they bulge outwards the blade will bind and can never cut a clean precise mortise, so corrections are absolutely necessary.
Mark any irregularities on your sketch.
Right Angled Sides
Sides angled with respect to the ura Slightly less than 90˚ may be acceptable (but less than ideal) on condition that both sides are the same angle. If, however, one side is 90˚, for instance, and the opposite side measures 80˚, well that is not good and may require correction.
The sides of the blade should be at right angles (90°) to the ura lands. If not, the chisel will skew left or right during each cut, a common problem with most chisels. Beloved Customer has no doubt experienced this.
For now, just mark any irregularities on your sketch.
Examine the Blade’s Face
Next, examine the chisel’s face (the surface with the brand stamped into it).
This oft-ignored surface need not be straight along its length. It doesn’t even need to be flat across its width. Indeed, it can even be be hollow or bulging to a minor degree without causing trouble. But you do need to pay attention to two key details.
First, if it is hollow or bulging, the curvature of the bulge or hollow across the blade’s width must be uniform. If not, you should grind it to be more uniform.
The second thing to check for is that a line between and touching the corners where the surface of the face meets the blade’s sides must be parallel with the ura. In other words, if you draw a line 90˚ across the width of the face, that line should be parallel with the ura. If it isn’t corrections are necessary.
Why does the relationship of these two surfaces with each other matter? Two reasons. First, if they are not properly aligned, and assuming the ura is flat, it means the blade is thicker in cross-section at either the right side or left side. There is a strong tendency for the bevel to become skewed during sharpening, with the result that the cutting edge is not square to the center line of the blade’s long axis.
Of course a skewed cutting edge will push the blade to the right or left in the cut, and cannot cut a flat bottom, a serious defect in advanced mortise and tenon work. This deformity can be compensated for with careful attention during sharpening, but you should not have to work so hard. Better to correct the problem now and get it over with once and for all, I promise.
The second and most important problem created by a skewed bevel is that it will cause the blade to dive to the right or left when cutting a mortise ruining precision and gouging the mortise’s walls. This is different from the problem noted in the previous paragraph, although it may seem to be the same. It’s a serious defect in a mortise chisel, one that causes the most self-doubt among craftsmen.
Even the very best blacksmiths frequently fail to give this surface proper attention. You are hereby warned: Do not underestimate the importance your chisel’s face.
Examine the Blade’s Corners
Finally, examine the two lines formed by the 90° intersection of the sides and the ura. Are they clean and sharp, or are they ragged, radiused or chamfered? These corner edges serve an important function in dimensioning and shaving the mortise’s side walls. They must be clean and almost acute enough to cut your fingers, but please don’t.
If they are not up to snuff you can make corrections now or a little bit at a time during subsequent sharpening sessions. The important thing is to be aware of any defects so you can make corrections, so make a note on your little sketch.
The Plan
You should now have a sketch describing those areas that need to be corrected. Use it to make a plan. A rough sketch showing how a mortise should should be and common problems is linked to below.
Beloved Customer should keep two important factors in mind in mind when planning and executing corrections to mortise chisels.
First, you should strive to achieve the corrections with the minimum expenditure of time, effort and stone/diamond plate, and while wasting the minimum amount of steel. I am not saying work hard or work fast, but rather to work efficiently.
Second, you should work carefully to avoid creating new problems while attempting to fix existing ones. This is why you need a plan, one that will vary a little with each chisel, to guide you in working efficiently and carefully. Remember, double work takes more than twice the effort and time, and often wastes a lot more expensive steel.
Correction Guidelines
The procedures your humble servant recommends for correcting a mortise chisel (or any chisel used for cutting mortises), based of course on the sketch you prepared, are as follows:
As mentioned above, the first step is to true the ura so it is planar. It need not be perfect at first; Close is good.
After the ura is more-or less planar, grind the right and left side of the blade, whichever is in better shape, straight along its length, flat (or sightly hollow) across its width, and perpendicular to the planar ura. If the angle between the ura and the sides is less than 90°, that’s OK too, so long as the angle of both right and left sides to the ura is the same. An angle here greater than 90° will cause problems and must be corrected. Diamond plates or diamond stones work well for these corrections. Electrical grinders and sanders can be used, but there is a real risk of ruining the temper if you allow the steel to get hotter than is comfortable to touch with your bare finger (seriously), so great caution is necessary. This means working slow and using lots of water.
When one side of the blade is true (perfection is not necessary), grind the opposite side straight along its length, flat (or sightly hollow) across its width, and perpendicular to the planar ura using diamond plates (if necessary). It will be at the same angle with the respect to the ura as the opposite side, of course, because the plane of the ura is the surface against which all others should be measured. Here is where more caution is necessary: pay close attention when grinding this side to make it parallel with the opposite side. If the blade width measured across the ura is slightly wider at the cutting edge than the neck, that’s fine too.. On the other hand, a blade narrower at the cutting edge than near the shoulders is useless for cutting mortises and must be corrected.
Finally, grind the face of the blade (the upper surface with the brand) so that any point along its length is parallel with the ura. It need not be straight or even perfectly flat over its entire length, just parallel with the ura to guide the chisel straight in the cut.
Beloved Customer has no doubt observed that it is entirely possible to succeed in executing one of the corrections in this list while making another worse. Please pay attention. This is why you made the drawing and a plan.
At the conclusion of the steps described in this article, your mortise chisel should now have an ura with all the lands surrounding the hollow-ground swamp forming a single flat plane.
Blade Color
The process of truing the blade’s face will remove some of the black oxide skin. If this changed appearance bothers you, use a chemical bluing/blacking solution such as Birchwood Casey products or those sold by Brownells should work well if used properly. The color may not perfectly match the black oxide finish fresh from the forge, and it won’t be as durable, but it should be less glaring than bright metal.
Blade Hardness
New chisels are often a bit more brittle than the specified hardness at the extreme edge, and may exhibit small fractures and/or chipping. This is a result of the cutting edge cooling quicker than the rest of the blade during heat treat and tempering.
This is not necessarily a bad thing, but to the contrary is often a sign of a well-made blade. A new chisel that is too hard at the extreme cutting edge when new may well improve after a few sharpenings, but one that is too soft and rolls an edge, or develops a burr, or, heaven forfend, dents in use will almost always be junk forever, unless it was burnt (lost its temper) during grinding, in which case it too may improve with a few sharpenings. I shared the story of Woody and the difficulties he experienced in the “Mystery of the Brittle Blade.” (soon to be out on NetFlix and starring Benedict Cumberbatch (ツ)】
Often the blacksmith or wholesaler will subcontract sharpening job out to a specialist. This practice allows the blacksmith to focus his attention on what he does best, which is a fine thing. But if the sharpener is careless or gets in a frikin hurry and burns the edges while grinding them, without exception the blacksmith gets blamed, resulting not only in an immediate financial loss and wasted time dealing with defective product claims, but a degradation of his valuable reputation. Having experienced this entirely avoidable damage, some blacksmiths, including our honorable plane blacksmith Mr. Nakano, insist on doing their own sharpening, or require the sharpener to work under their eye in their smithy, as does Konobu, to avoid this problem.
Bevel Angle
Bevel angle is critical to cutting edge durability. I recommend maintaining a bevel angle of at least 27.5°. 35° is even better when cutting harder woods.
You should use a bevel angle gauge of some sort to check the angle during each sharpening session.
You may be surprised how the angle will become gradually smaller with each sharpening if you don’t do this check. Even professionals frequently allow the angle to wander by mistake or through supernatural influences. There are several useful gauges commercially available for this purpose, or you can easily make one from scrap brass or aluminum.
In future articles we will consider the feeding of the Wild Mortise Chisel. They are fastidious diners, after all.
Until then, I have the honor to remain,
YMHOS
A formal procession of frogs mocking the feudal lords of medieval Japan. I bet you haven’t seen many frogs walking around with swords. Such work was a rare opportunity for artists and the common people to mock the rich and powerful nobles that ruled the many little feudal nations of the Japanese islands at the time with a despotic fist.
If you have questions or would like to learn more about our tools, please click the see the “Pricelist” link here or at the top of the page and use the “Contact Us” form located immediately below.
Please share your insights and comments with everyone in the form located further below labeled “Leave a Reply.” We aren’t evil Google, fascist facebook, or thuggish Twitter and so won’t sell, share, or profitably “misplace” your information. If I lie may my mortise chisels all turn to glass.
Other Articles in “The Care and Feeding of the Wild Mortise Chisel” Series
Covington & Sons Tools 
Leave a comment