A Few Masterpieces

“Living by faith includes the call to something greater than cowardly self-preservation.”

J.R.R. Tolkein

In this post your humble servant will present a few modern masterpieces of the blacksmith’s art produced recently by a single craftsman. I hope you are as thrilled as I am to know there is at least one craftsman left in the world that can produce chisels of this quality.

The Blacksmith

The craftsman that made these chisels is very unusual in that, unlike the frantically self-promoting, technically mediocre Hollywood blacksmiths such as Tasai, Funatsu, Kiyohisa, and the modern Chiyozuru gang, he is reclusive and shuns attention. Accordingly, I have been requested to not share any personal details about him, so please don’t ask. The fact is I don’t even know his real name just the brand he uses.

I won’t discuss why he is reclusive, but I will go so far as to say that he is self-employed, well-known in his chosen field, and that chisels are not his primary work product but only a sideline. He makes no more than 5 chisels monthly.

His business philosophy and blacksmithing techniques are interesting so I will share some details about them. He has four strict requirements that a Customer must satisfy before he will accept an order. The first two are business-related, and the last two are about the Customer.

  1. The Blacksmith sets the delivery schedule. Period.
  2. The Blacksmith sets the price. Period
  3. The Customer must be a professional worker in wood who needs and will use the tools the Blacksmith will forge daily. His track record must be independently verifiable. Amateurs and/or hobbyists, regardless of their skill levels, need not apply. Collectors are specifically unwelcome.
  4. Besides being expert in the use of chisels, the Customer must have a minimum level of skills, including the ability to make chisel handles and cut a high-quality Japanese plane block using only hand tools. Once again, this must be verified before an order will be accepted.

Your humble servant commissioned a few chisels from the Blacksmith many years ago and went through this same qualification process, although I didn’t realize it at the time.

The quality of his forging and heat-treat technique is unsurpassed producing a crystalline structure in hard steel that will take an extremely sharp edge, will hold that edge without easily dulling, chipping or rolling while cutting a lot of wood, and is easily sharpened.

But it is his metal shaping and finishing skills that are so awe-inspiring. Please notice the straightness and cleanness of the lines and planes, as well as the uniform and smooth curvature at the shoulders, and perfect symmetry. If Gentle Reader is unimpressed, I encourage you to make a full-scale model from cold wood before trying it in hot metal. I promise you will be convinced.

The Blacksmith uses only “free-forging” techniques, and does not employ the rough shaping dies other modern blacksmiths rely on to improve production speed. His forging technique is so sublime that the entire chisel is shaped to nearly final dimension by fire and hammer, not grinders and belt sanders.

He finishes his products using only hand-powered scrapers (sen) and files.

The performance of Blacksmith’s products are equal to or better than those of Kiyotada back in the day, and are more precisely shaped and more beautifully finished than those of Ichihiro (the Yamazaki Brothers) at their very best. They are simply the best chisels that have been made in Japan in the last 70 years.

Let’s take a look at four chisels recently completed for a Beloved Customer in the USA.

34 x 485mm Anaya Chisel

The Anaya chisel is an antique style used for cutting deep mortises and making other joints in large timbers. It is no longer commercially available.

Top view of a Anaya 34x485mm Anaya chisel
Ura view of 34x485mm Anaya chisel
Side view of 34x485mm Anaya chisel

57 x 485mm Anaya Chisel

42 x 490mm Bachi Nomi

The Bachi nomi is the equivalent to the fishtail chisel in English-speaking countries. The word bachi comes from the splayed tool used to play the 3-string Japanese shamisen, a banjo-type musical instrument. Here is a link to a video of two ladies using shamisen and bachi to perform a famous traditional song in Tokyo.

The Bachi nomi excells at getting into tight places to cut joints with acute internal angles such as the dovetail joints that connect beams to purlins.

There are several ways to resolve the angles at the tool’s face, but in this case the Beloved Customer and Blacksmith agreed on the most difficult, rigid and beautiful solution, the shinogi. This design has the advantage of maintaining a shallower side-bevel angle from cutting edge to neck return providing better clearance in tight dovetail joints.

The handwork performed on this chisel’s face is simply amazing, but the hollow-ground ura is even more spectacular to those who know about this things.

54 x 540mm Sotomaru Incannel Gouge

The Sotomaru or incannel gouge is a strong and convenient chisel used for cutting joints in logs and rounded members on architecture. More information can be found at this link.

This is an especially beautiful example as seen the symmetrical confluence of planes and curves at the shoulders.

Conclusion

I hope Gentle Reader found this post informative. You will never find better examples of the Japanese blacksmith’s art outside of one particular museum. It is exciting to consider that there is still one craftsman alive that can routinely perform this level of work.

While your humble servant has praised these chisels and the blacksmith that made them highly, please do not make the mistake of assuming that I am soliciting orders, or even suggesting that commissioning them is possible, because they are simply not available at any price. Please don’t ask.

YMHOS

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. May my ootsukinomi roll from my workbench and land cutting-edge down on my toes if I lie.

The Care and Feeding of the Wild Mortise Chisel – Part 1

Sukezane brand 9mm mortise chisel (mukomachinomi) side view

It is well with me only when I have a chisel in my hand

Michelangelo 1475-1564

This is the first in a five-part series about the Mortise Chisel, especially the Japanese version.

Also called the “Joiner’s Chisel” in Japan, this is a specialized chisel used by specialist craftsmen to cut precise, smallish joints when making furniture, cabinetry and joinery. Carpenters don’t use it, and few have in that august trade have even seen one.

In this post your humble servant will introduce a tiny bit of the terribly long history of the mortise and tenon joint, and give a description of this specialized chisel.

In future posts we will look at how to evaluate, adjust and even how to use the Mortise Chisel in general and the Japanese Mortise Chisel in particular. We will also touch on bevel angles and blade hardness problems.

We will discuss what to look for in a good mortise chisel and how to examine it with an eye to increasing its performance. This is something most users of chisels never consider, but it can make a big difference in the case of mortise chisels. Indeed, I daresay most Gentle Readers will mutter the equivalent of “Bless us and splash us” when they read it.

Of course we will also discuss how to effectively correct irregularities in our mortise chisel that negatively impact performance, irregularities most people never notice.

After our Mortise Chisel is properly fettled (they almost always have some problems) we will take our racing chisel out for a few laps, but prior to that we will consider how to effectively use this specialized tool. Too few receive proper training nowadays in chisel work, but here are C&S Tools we feel it our duty to help our Beloved Customers improve their skills.

We will conclude this series by taking the “Old Master’s Test,” just to make sure both our Mortise Chisel and our skills are improving.

While focused on the Japanese Mortise Chisel, the principles and improvements discussed in this series of articles are applicable to any chisel used to cut mortises.

While all Gentle Readers with eyes to see, ears to hear, and hands that love wood are welcome to share this hard-earned knowledge, it is intended primarily for our Beloved Customers, especially those who use chisels professionally to keep body and soul in close proximity.

Some Background

Your humble servant drafted this series of posts years ago, and has shared bits of it with Beloved Customers from time to time when requested, but the information has not always been well-received for a number of reasons.

There is an old Japanese saying, one which probably originated in China, written 「馬の耳に念仏」and pronounced “Uma no mimi ni nenbutsu,” which translates to “Prayers in a horse’s ear.” Why are Buddhist prayers relevant you ask? Good question. You see, some of the principles I will present in this series directly contradict doctrine taught by some of the Holy Woodworking Gurus in the West. Like vespers to a beast of burden, wisdom is wasted on the willfully, woefully ignorant (wow, that almost sounds like iambic pentameter!).

But our Beloved Customers are neither horses nor asses nor politicians but shockingly intelligent human beings to whom your humble servant is convinced the time has come to expound the gospel of the Mortise Chisel as it was taught to me by Masters who have since abandoned this impure world for more ethereal realms.

This series of posts is equivalent to a graduate school course in chisels, something like “Mortise Chisels 701.” And just like a course in advanced differential equations, most Gentle Readers will never need it. But never let it be said that your humble servant didn’t do his best to improve both the skills and the tools of our Beloved Customers.

Some History of the Mortise & Tenon Joint

Mortise chisels are used for cutting rectangular holes in wood usually intended to accept tenons to form a structural connection called the “mortise and tenon joint” between pieces of wood.

No one knows how long humans have been using the mortise and tenon joint, but it has certainly been longer than nails, and many thousands of years longer than screws, although modern humans with their lithium battery-powered, made in China, landfill-bound, multicolored plastic and rubber screwdrivers may find it difficult to imagine. So let’s begin the journey by briefly examining just two well-documented extant physical examples that may provide motivation for using this enduring joint.

The oldest known wooden structure is a neolithic well liner discovered near Leipzig Germany, constructed from oak timbers shaped by stone adze and joined at the corners with half-lap joints and pinned tusk-tenons at through mortises. Tests indicate the trees the timbers were split from were felled between the years 5206 and 5098 BC, making the assembly at least 7200 years old.

Next, let’s look at a less soggy but more recent, complicated and elegant example.

The oldest existing wooden building in the world is a Buddhist Temple named Horyuji located in Nara Japan. Originally constructed around 600 A.D. and rebuilt around 700 A.D. after a fire, this huge 1300 year-old temple and pagoda complex was reconstructed using hundreds of thousands of hand-cut mortise and tenon joints, testifying to the longevity of wooden structural systems and the value of this universal connection technique.

Horyuji  is far more than just a temple to Buddhism, it is a temple to woodworking. If you haven’t yet visited it, you’re truly missing something. 

I mention these two examples to illustrate the universality, strength, and durability of the mortise and tenon joint. Anyone serious about woodworking must master this most ancient and essential connection.

The mortise chisel is the best handtool for the job of cutting mortises less than 15mm in width. For wider mortises, well-fettled oiirenomi or atsunomi are more efficient.

Japanese Mortise Chisels

12mm mortise chisel (mukomachinomi) Face View
12mm mortise chisel (mukomachinomi) Side View
12mm mortise chisel (mukomachinomi). Please notice the rectangular cross-section precise right angles, and straight, clean sides. This is the most precise of the Japanese chisels.

In the Japanese language mortise chisels are called “mukomachi nomi” (向待鑿), with “nomi” meaning “chisel.” Don’t ask me the origin of the rest of the word because I don’t have a clue, and have heard few plausible explanations. There is another post linked to here that contains more information about this chisel.

I will use the term mortise chisel in this article to refer to mukomachi nomi.

For our Gentle Readers interested in the Japanese language, there are several combinations of Chinese characters used to write mukomachi, none of which make much sense or seem related in any way to either tools or woodworking. The most common characters used are “向待” with the first character meaning “there” or “direction,” and the second character meaning “wait.” Combined, they seem to mean “Waiting over there,” or something like that.

I assume the name was originally phonetic and somebody decided to use these kanji because their pronunciation matched the phonetic name. This sort of linguistic contortion is seen frequently in Japan, and has been a source of confusion for all and sundry for many centuries. I blame it on elitist Buddhist priests going back and forth between Japan and China over the centuries, but it is typical of the Japanese people in general and priests in particular to take a perverse pleasure in intentionally making and using terms others can’t figure out.

This confusing practice is not unique to bald priests. When I was an engineering student, I recall the professors insisting we never attempt to simplify or too clearly explain the technical jargon of the trade to non-professionals because it was essential to job security for them to never quite understand it.

If you are familiar with Japanese architecture, you have seen the wooden lattice work that defines it in doors, windows, dividers, shoji, fusuma, koshido, glass doors, ceilings, and even fences, all items made by “tategushi” or “joiners” in Japan. Each piece of any lattice needs two tenons and two matching mortises to stay in-place, so a single piece of traditional Japanese joinery may have literally hundreds of small, very precise mortises, indeed thousands in the more complicated pieces. The Japanese mortise chisel was developed specifically at the request of joiners for this type of work. Therefore, it is also known as the “Tategu Nomi” which translates to “joinery chisel.” Few carpenters use this chisel.

Nora Brand 6mm Mortise Chisel (Mukomachinomi) Side View. Although it appears to be a simple, unsophisticated tool, nothing could be further from the truth. Based on the Kiyotada pattern, this is an especially beautiful example to those with eyes to see.
Nora Brand 6mm Mortise Chisel (Mukomachinomi) Ura View
Nora Brand 6mm Mortise Chisel (Mukomachinomi) Shoulder View. Exceptional shaping and filework .

Japanese mortise chisels are similar to other Japanese chisels in having a laminated steel structure with a hollow-ground ura (flat), an integral tang, wooden handle, and steel ferrule and hoop. Unlike most other chisels it has a rectangular cross-section with sides usually oriented 90˚square to the hollow-ground ura, and either flat or just slightly hollow-ground to better keep the blade aligned in the cut and to dimension and smooth the mortise’s walls.

Western mortise chisels do not typically share this detail, although unusually intelligent and observant Western woodworkers of course modify their chisels to gain similar benefits.

If speed and precision are important to you, then the sides of the chisel being oriented at 90° to the ura absolutely provide a serious advantage when cutting most mortises because the sides, and especially the two sharpish corners where these three planes meet, will effectively shave and precisely dimension the mortise’s side walls as the mortise is being cut without the need to pare them later.

Unlike most mortise joints cut with oiirenomi or atsunomi, so long as the mortise is the same width as the mortise chisel, and the user has the ability to maintain the chisel at the right angle while striking it with a hammer, the width of mortises cut with this chisel are usually quite precise and seldom if ever need be cleaned with a paring chisel. This functionality means that you can cut mortises, and especially small ones, both precisely and quickly with great confidence. It’s not called the “joiner’s chisel” for nothing.

The mukomachi chisel does not work as well in wider widths because of the increased friction between the chisel’s sides and the mortise’s walls. For joints wider than 15mm, please use a trued oiirenomi or atsunomi. And don’t forget to use your oilpot.

In the next class in our graduate course on the care and feeding of the wild mortise chisel, we will examine the various details to look for in an effective mukomachi nomi. Most of these details are applicable in the case of other chisels such as oiirenomi and atsunomi too, indeed any chisel intended to be used to cut mortises including Western mortise chisels.

But wait a minute! Before ya’ll run out of the classroom like a caravan of crazy stoats chasing a pixie, please pick up your homework assignments from the table by the exit doors. And please, don’t leave your empties behind on the floor. Paper coffee cups are one thing, but diascarded aluminum beer cans attract out-of-work divorce lawyers and other such desperate vermin.

See you next time.

YMHOS

Your most humble and obedient servant’s set of well-used mortise chisels. The 8 older pieces on the right are by Kiyotada (1.5mm~15mm). The two 2 newer chisels on the far left are by Nora. Over the years I have used these tools both professionally and as a hobbyist more than any other of my chisels, as you can perhaps tell from the differing blade and handle lengths which have become shorter with use. A stoic tool, they gossip among themselves less than most other chisels. They are good friends and reliable workmates that worked hard for many years to pay rent, tuition and food for the wife and babies.

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 Mama Shishi bite my head off.

YMHOS

Other Articles in “The Care and Feeding of the Wild Mortise Chisel” Series

The Varieties of Japanese Chisels Part 16 – High-speed Steel Atsunomi

I am past scorching; not easily can’st thou scorch a scar.”

Herman Melville, Moby-Dick or, the Whale

We have presented 15 varieties of Japanese chisels for your consideration at this blog to-date. In this post we will examine a specialized version of the Atsunomi previously presented in Part 8 of this series, made from high-speed steel.

The C&S Tools High-speed Steel Atsunomi

The chisel in question is made by Mr. Usui Yoshio of Yoita-cho, Nagaoka City, Niigata Prefecture, under his brand name of Sukemaru. The shape of this tool is identical to his standard atsunomi, the only significant differences being the type of steel used and the bright appearance of the blade.

This is not a small chisel but a professional-grade, rugged tool with an overall length of approximately 300mm (12″). It is an indispensable tool in some situations.

If you need a smaller, handier, and more economical HSS chisel, please take a look at our HSS Oiirenomi also by Sukemaru.

What is High-speed Steel?

So just what is high-speed steel (HSS)?

HSS is a tool steel developed for manufacturing commercial cutters, dies, etc. In this case, Usui-san uses a high-speed steel designated SKH51 in Japan, the equivalent to M2 in the USA, BM2 in the UK, HS6-5-2 in Germany, and Z85WDCV06-05-04-02 in France. This is the most popular HSS formula in the world. If you own router bits without carbide cutters, and not made in China, you own this steel.

This variety of HSS contains buckets-full of tungsten, molybdenum, chrome, with a stout vanadium chaser.

After oven heat-treat, these chemicals make the steel tougher, more abrasion-resistant, and more resistant to softening (aka “temper-loss”) when subjected to high-temperatures than regular high-carbon steel. Its nickname of high-speed steel comes from the tendency of cutters made from this steel to retain their hardness even when worked so hard blade temperatures become hot enough to draw the temper of standard steel cutters, softening and making them useless.

The chemical composition is listed below, just in case you are interested. You can see what I mean about “buckets.”

CMNSiCrWMoV
0.85%0.28%0.30%4.15%6.15%5.00%1.85%
Chemical composition of SKH51/M2 HSS Steel

Why Use High-speed Steel?

The next question in Gentle Reader’s mind, no doubt, is “what are the properties of high-speed steel and what difficulties can a chisel made from this special steel help me overcome?”

Toughness and Shock Resistance

Perhaps the most significant property of high-speed steel is its toughness. SKH51 (M2) steel is the most shock-resistant of the high-speed steels, making it especially suitable for use in a chisel that may impact hard objects in daily use but must survive without chipping or breaking. This toughness provides huge benefits in the situations described further below.

Abrasion Resistance

Abrasion resistance goes hand-in-hand with toughness, but it is a different characteristic many misunderstand. It does not mean a cutting edge will be sharper than a cutter made of high-carbon steel, only that it won’t wear and become dramatically rounded-over as quickly. In the case of chisels, a blade made from highly abrasion-resistant tool steel will reach a certain level of sharpness (or dullness) and remain at that level a relatively long time allowing a cutter to keep on cutting without becoming useless. But the quality of the cut will decrease, and energy necessary to motivate the blade will of course increase as the blade dulls. No free lunch, sorry to say.

Abrasion resistance is not typically considered overly important in blades where great sharpness is given priority, but it is extremely important when the blade is used to cut materials such as exotic hardwoods that contain silica crystals, or Engineered Wood Products that contain hard adhesives and/or highly-abrasive particles such as silicon carbide deposited by sandpaper, or dirty wood contaminated with sand, grit and other contaminants that will literally destroy the cutting edge of a plain high-carbon steel blade making it useless.

Just as a strong truck would be at a hopeless disadvantage in a Formula One race, a McLaren MP4/6 with all its speed, power and agility couldn’t tow a heavy trailer 100 yards through the mountains. Horses for courses.

Engineered Wood Products

One major challenge the HSS atsunomi excels at overcoming is modern wood products called Engineered Wood Products (EWP)

Commercial carpenters and cabinet makers nowadays have no choice but to use modern EWP such as plywood, MDF, HDF, OSB, LVL, glulams, etc.. Unlike new, clean, solid lumber cut with saws and planed with knives to final dimensions, engineered wood products are comprised of wood veneer, chipped wood and/or sawdust glued together by hard adhesives that will harm standard steel tool blades. HSS handles these difficult adhesives easily.

A bigger problem associated with EWP is the extremely hard abrasive particles left embedded in them by the sanding belts used to dimension and smooth them, particles much harder than any heat-treated steel, that will quickly destroy a good high-carbon steel chisel. Being much tougher and more abrasion resistant than high-carbon steel, HSS can handle this abrasive residue without being destroyed. That does not mean abrasive particles do not scratch and dull HSS atsunomi cutting edges; After all, silica carbide particles are harder than high-speed steel. It just means they won’t chip or break and will keep on cutting longer than HC steel blades.

Restoration & Remodeling Work

Another type of work this HSS atsunomi excels at is restoration work, remodeling work, and chisel work around concrete and masonry.

In the case of restoration work, the job usually involves cutting wooden structural members and finish materials that are old and dirty and contain hard abrasive dirt, sand, small stones and of course hidden nails and screws that will not only dull a chisel blade but may badly chip it. 

For instance, a Beloved Customer who is a timber-frame carpenter in the Czech Republic was tasked with splicing segments of new timber to replace rotted-out sections of a large number of 300 year-old rafters during the ongoing restoration of the Grand Priory Palace located in Prague (constructed from 1726 to 1731), an ancient city with many beautiful, old structures.

Grand Priory Prague
Grand Priory Prague
Grand Priory Prague Roof Frame Restoration
Grand Priory Prague Roof Frame Restoration

The wood was dirty and full of gravel and broken-off nails that chowed down on standard chisels without pausing for a drop o’ Tabasco Sauce. But our HSS atsunomi chisel made it possible for him to cut and fit the timber splices while working on the steeply-slanted roof far above cobble-stone streets without chipping the blade and without stopping the work for frequent resharpenings beyond an occasional touchup with a belt sander.

In the case of remodeling work, one must routinely cut precise holes through existing wood contaminated with abrasive dirt and hiding screws and nails, as well as lathe, plaster and drywall containing abrasive sand, and in close proximity to mortar and concrete which contains sand and gravel aggregates that will dull, chip and even destroy a standard chisel in two shakes of a lamb’s tail. 

If you have ever done remodeling work or an installation requiring chiselwork, you know the despair one feels when gazing upon the damage done to a beloved tool.

Likewise, during installations, cabinetmakers must make precision cuts in abrasive engineered wood products such as plywood, OSB and MDF. Our HSS atsunomi chisel, as well as our HSS oiirenomi chisel excel at this job being far more durable than standard chisels with high-carbon steel blades.

Jigane

The jigane Usui-san uses for his HSS Atsunomi is a harder version of the standard low-carbon steel he uses for his standard atsunomi. It is not stainless steel, however, and can corrode.

Likewise, the furniture (katsura (hoop) and kuchigane (ferrule)) are made from mild steel, not stainless steel, despite the bright appearance, and will exhibit corrosion over time. As an option, these two parts can be ordered blackened creating a two-toned chisel some people find attractive.

Heat-treat and Hardness

To prevent chipping, the HSS blade is heat-treated in a special computer-controlled oven following a specific temp/time curve to achieve a hardness of Rc63, intentionally a little softer than the maximum hardness of Rc64 listed for this steel. Even then, this is harder than nearly all currently-produced Western chisels we are aware of. 

The blade’s bevel angle is 30°, the standard angle for Japanese woodworking chisels. To reduce denting you may want to increase the angle to 35° if you will be cutting through hard materials.

Resharpening in the Field

Another huge advantage of Sukemaru’s HSS chisels is that they can be quickly resharpened to a usable cutting edge in the field using angle grinders and belt sanders without losing temper and softening so long as one is careful to keep temperatures below 650°C (1200°F), not difficult to do if one pays attention. Don’t underestimate the efficiency this feature will bring to your work some days.

The compromise with HSS chisels is that, while they can be made extremely sharp using stones and proper technique, they will never become as sharp as our hand-forged high-carbon steel chisels. Moreover, they will take twice as long to sharpen by hand using conventional wetstones and waterstones.

Sharpening time can be reduced dramatically by using aggressive diamond plates or diamond stones.

We have personally tested these chisels to failure and resharpened them. We are confident of their quality and performance.

If you need an exceptionally tough chisel that can “take a lickin and keep on tickin” even in conditions that would utterly destroy a regular chisel, then the HSS Atsunomi, or where a smaller tool is required, its tough little brother the HSS Oiirenomi, will get the job done for you.

If you would like to know more about these chisels, please drop a note in the form below titled “Contact Us.”

YMHOS

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. May a thousand bot flies make a home in my eyebrows if I lie.

Links to Other Posts in this Series

The Varieties of Japanese Chisels Part 15 – Ootsuki Nomi 大突き鑿

All times are good for those who know how to work and have the tools to do so.

Carlos Slim

The Ootsuki nomi is the largest of the Japanese chisels. It is essentially a scaled-up tsukinomi paring chisel, equivalent to what is called a “slick” in the West.

Definitions

The name is written 大突鑿 using Chinese characters. The first character 大 means “large,” or “ big.” Besides “Oo “ this character can also be pronounced “dai.” You may notice it looks like a man with his legs spread and arms extended, as if he is describing to his buddies the size of the fish that got away. At least that’s how I remembered the meaning when I was a young man in Japan many moons ago.

The second character 突 means to “push against.” And the last character 鑿 , pronounced “nomi” means chisel. It is a very complicated character the origin of which is a mystery to me and everyone I have asked.

So the name translates directly to “large push chisel.”

Applications

If you have never done timber framing, a brief explanation may be helpful. 

When doing production work (versus hobby stuff) one cuts the pieces and parts of most open joints using electrical circular saws. Chainsaws kinda work too, but with much less precision.

Handsaws are also necessary for some cuts, but for most situations a circular saw is much quicker and less tiring. There’s a lot of wood that needs cutting after all and only so many hours of daylight.

Mortises are typically cut with portable electric hollow-chisel machines. There are other options such as portable chainsaw mortisers, stationary router machines, or the amazing German Hundegger machines. http://hundeggerusa.com

I once worked for a Japanese company that cut entire structural frames using CAD driven CNC machines in a factory. In that situation however, the CNC machinery, while very precise and very quick, was so expensive and so inflexible that the building had to be designed around the repertoire of joints and sizes the machinery could cut rather than the joints required to make the best building. And it could not handle significant dimensional irregularities in the timbers used, so only machined glulams were suitable. A very limiting endeavor indeed. I left that job after 2 years.

Sharp tools guided by human hands, controlled by human minds with years of experience are more flexible.

Paring a saddle
Paring a splice joint with a 48mm chisel
Paring a housed semi-half-lap notch where two beams will cross over and under each other

Indeed, handtools like axes, adzes, chisels and handsaws are necessary especially when doing “ round work” in logs or when the design calls for irregular-shaped timbers. Paring chisels are also needed to achieve the relatively precise tolerances and smooth surfaces such work demands.

Ootsuki nomi are relatively heavier than other Japanese paring chisel with larger diameter and longer handles. They are  built to resist the large bending moment forces created by a large man gripping the handle with both hands and pushing like a plow horse to pare wood. This is the task this chisel excels at.

Most Japanese carpenters that use this tool buy them in sets of two: a wide 48~54mm wide one for paring open joints and the sides of mortises, and a narrower 24mm chisel, although other sizes are available. I have owned a custom 2-pc set hand-forged for me by Mr. Shimamura (Kiyotada) many years ago, one with a 60mm blade and an extra-large handle intended for working especially large North American  timbers. 

The 24mm chisel is used for paring standard rectangular mortise, dovetail mortises and dovetail tenons, besides a hundred other tasks. In cross section, it is essentially a large shinogi usunomi chisel to help it get into tight places.

A carpenter paring the end walls of a mortise with a 24mm ootsukinomi chisel

Mitsuura

When paring large surfaces with the wider ootuskinomi chisel the hollow ground ura may allow bumps to slide in the hollow-ground ura unseen escaping paring requiring multiple passes to knock them down. This sneaky behavior is easy to overcome with practice, but some people prefer an ura with not a single, but multiple grinds with lands between each hollow-ground area to help index the blade and shave these bumps the first time.

I believe this is one of the few situations where these multiple ura, called mistuura or “triple-ura” are useful.

Kensaki (swordpoint) Ura by Sukemaru. A very unique style of mitsuura cut with EDM equipment. Pretty cool, huh. Sadly, Mr. Usui no longer does this detail no many how hard I beg him to.

Some people like the unusual appearance of mitsuura. I must admit they look sexy in wide blades, but they have some downsides. The first downside is that, because there is more hard steel in contact with the stone, mitsuura blades can take a little longer to sharpen.

Second, they can be a little harder to keep flat. Neither of these are difficult problems to overcome. But the third downside is more problematic. 

A worn-out mitsuura oiirenomi

Because the three hollow-ground areas are shallower and have less total volume than a single ura, they tend to wear out and disappear sooner. This is not a serious deficiency unless you use and sharpen a mitsuura chisel a lot, or have a heavy hand when sharpening the ura. The negative impacts are minor in most cases.

Beloved Customers need to be aware of these peculiarities and to be gentle when sharpening mitsuura blades.

C&S’s 24mm Ootsukinomi. Notice the shinogi shape

These are not chisels most people will ever have need of but as long as humans are doing timber framing, there will always be a demand for this unique tool.

C&S’s 24mm Ootsukinomi (face)
C&S’s 24mm Ootsukinomi (side)
C&S’s 24mm Ootsukinomi (Ura)
C&S’s 48mm Ootsukinomi (mitsuura)
C&S’s 48mm Ootsukinomi (side)

YMHOS

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If you have questions or would like to learn more about our tools, please 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, incompetent facebook, or troublesome Twitter and so won’t sell, share, or profitably “misplace” your information. May my feet turn to lead and fall off if I lie.

The Varieties of Japanese Chisels Part 14 – The Kote Nomi (鏝鑿Trowel Chisel)

You cannot mandate productivity, you must provide the tools to let people become their best.

Steve Jobs

This post will be a little different from my normal post for several reasons. First, because although I love this tool, I have a difficult time procuring them anymore, so it is more of a show and tell. And second, because I have a couple of stories to tell about the blacksmith that made it, and the store that sold it to me.

The Kotenomi

The kote nomi is written 鏝鑿 in Chinese characters meaning ” trowel chisel.” It is not an elegant name, but is accurately descriptive. It is essentially the same as the Western ” cranked-neck chisel. ” It is used to pare grooves, dadoes, sliding dovetails, rabbits and mortises, anywhere the handle of a regular paring chisel would get in the way.

The sides have a steeper bevel than regular chisels, much like a shinogi usunomi, to help it get into tight places and cut right up against the sides of sliding dovetail groves, dadoes, etc..

These are not easy chisels to sharpen because of both the offset, and the tendency for the neck to get in the way.

This is one of those chisels that you may not need often, but when you do need it, you need it badly.

Kiyotada Kotenomi 21mm (Left Face View)
Kiyotada Kotenomi 21mm (Face View)
Kiyotada Kotenomi 21mm (Ura View)
Kiyotada Kotenomi 21mm (Right Shoulder View)
Kiyotada Kotenomi 21mm (Face View CU)

The shape of the two Kiyotada kotenomi shown in the 10 photographs on this page is graceful, elegant and minimalist. The filework is very nice. The black oxide skin is consistent, indicative of a perfect heat treat. The blade, made of Shirogami No.1 steel (aka “White Steel 1”) is, unsurpassed by anything I have experienced. It is one of those rare tools that clears the mind as it cuts wood.

Background

The kotenomi in the pictures above have an interesting back story. It was forged by a famous and exceptionally skillful blacksmith named Kosaburo Shimamura (島村幸三郎)using the brand ”Kiyotada” (清忠). It is not the standard Japanese kotenomi in terms of design, appearance or performance, but is based on those forged by an even more famous blacksmith named Hiroshi Kato (加藤廣1874-1957) under the name of Chiyozuru Korehide (千代鶴貞秀), one of Japan’s greatest tool designers and blacksmiths. Much of his work is seen as great works of art in Japan.

As Mr. Ichiro Tsuchida told the story to me, he lent one or more of his collection of Chiyozuru Korehide kotenomi to Mr. Shimamura and asked him to forge some just like it to sell in his tool store Sangenjaya in Tokyo. After much trial and error, Mr Shimamura succeeded in approximating the Chiyozuru design in the chisels shown here.

As you can see from the pictures, the blade’s sides are sloped inwards from ura to face, a detail that provides clearance when cutting sliding dovetails, a joint this tool excels at making.

I use it, as well as my other Kiyotada kotenomi, for making dadoes, rabbets, and inletting swamped rifle barrels in reproduction flintlock barrels (sadly, I can’t pursue that activity here in Japan).

Kiyotada Kotenomi 9mm (Face View)
Kiyotada Kotenomi 9mm (Ura View)
Kiyotada Kotenomi 9mm (Right Side Neck View)
Kiyotada Kotenomi 9mm (Left Side View)

Kiyotada Kotenomi 9mm (Left Face View)

The following are pictures of the standard garden-variety kotenomi.

As you can see, the standard kotenomi are very clunky in appearance and crudely finished compared to Shimamura’s chisel, with a more abrupt, angular transition between neck and blade, whereas the handle in the Kiyotada design approaches the neck at more of an angle, a detail that stiffens the neck, reduces the bending moment on the neck/blade junction, and helps force flow into the blade more smoothly.

The standard model works just fine, but a comparison of their the appearance and tactile qualities would be like a Lear jet and Cessna 172: both vehicles will get you there, but the speed, comfort and style will vary.

Standard kotenomi chisel (face view)
Standard kotenomi chisel (Right shoulder view)

The Kiyotada Brandname

A bit if trivia some may find interesting. The Kiyotada brandname was registered by, and remains the property of, a tool store in Tokyo called ” Suiheiya” (水平屋).

Suiheiya means ”level store,” probably named for the bubble-level tool imported from the West and which is so critical to construction and other trades. This store is old and was once the largest tool retailer in Japan. Last time I visited it was still large and packed to the concrete rafters with planes and chisels.

I first visited Suiheiya when I was a student in Tokyo in the ‘80’s when the premises was a 2-story wooden structure probably built right after the end of WWII. The proprietor was an old sourpuss who had no patience with foreigners and treated me like a shoplifter-in-training with a turd perched on my head. For some reason I can’t put my finger on I didn’t visit the store frequently, but I did buy this and other tools from him.

But I digress. Shimamura San made chisels and knives for Suiheiya his entire career and marked those tools with Suiheiya’s own Kiyotada brand. I suppose it would have seemed silly, or at least confusing, to mark a chisel or knife with a brand that could only be read as ”bubble level.”

I’m unsure how it happened, but as his products became more famous Shimamura-san made chisels for other retailers using the same Kiyotada brand. I was told by the owner of Suiheiya that Shimamura-san used the Kiyotada brand for all his products with Suiheiya’s permission.

By the way, although Shimamura-san has gone to the big lumber yard in the sky, Suiheiya continues to sell planes and chisels with the Kiyotada brand, although they are not made by Shimamura-san, who is busy with more important matters nowadays.

Sadly, my blacksmiths won’t make kotenomi for me anymore. I tend to be picky about quality, and with Kiyotada’s kotenomi as the standard, you can see why customer satisfaction in my case is difficult.

YMHOS

© 2019 Stanley Covington All Rights Reserved

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If you have questions or would like to learn more about our tools, please 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, incompetent facebook, or troublesome Twitter and so won’t sell, share, or profitably “misplace” your information. May the fleas of a thousand camels infest my armpits if I lie.

The Varieties of Japanese Chisels Part 13 – The Shinogi Usunomi 鎬薄鑿 Paring Chisel

Kiyotada Shinogi usunomi

“All times are good for those who know how to work and have the tools to do so.”

Carlos Slim

The shinogi usunomi is another variety of paring chisel in the tsukinomi family.

We examined the word ” shinogi” in a previous post.

It means ”ridge” as in the ridge of a mountain, or a building’s roof, or the back of some Japanese swords. Shinogi-style chisels have two wide bevels on their face that meet at the bade’s centerline creating a ridge. Sometimes there is a narrow flat at the top of the ridge, depending on the blacksmith’s style and customer request.

If the atsunomi is the draught horse, the oiirenomis are the quarter horse, and the usunomi is the falcon of the chisel world (the one in my slightly addled head, that is), then the shinogi usunomi is a Goshawk, severe in appearance, fierce, strong, fast, and skilled at maneuvering nimbly in tight situations.

Shinogi usunomi have these same two bevels and center ridge as the shinogi oiirenomi. The side edges tend to be thinner than standard usunomi, and with less material in the way, they are often just the ticket for paring into right corners. And because the ridge is higher than the standard usunomi is thick, they tend to be a bit more rigid.

And of course, since it is an usunomi (meaning “thin chisel”) it has a relatively longer and more slender neck and handle, and no crown.

A pox on anyone that would strike one of these beauties with a mallet or hammer.

One downside to this design is that the ridge down the face, which increases the overall thickness of this chisel, may make it difficult to pare down into skinny mortises. Another potential downside, but not one that bothers me, is that the ridge is not as comfortable to press on with your fingers when paring. I find this ridge gives my fingers a better sense of the blade’s precise location in my hand and in the cut. This is all personal preference that can only be evaluated through experience using both varieties of usunomi.

You may be able to tell from my choice of words that I am fond of shinogi usunomi. Indeed, I admit to prefering them. I like how they look. I like how they feel. I like sharpening them. I like how they cut. I like how the extra clearance on the side lets me see what I am paring. Subjective? Of course. And I admit they can’t do all jobs. The standard usunomi is probably a better general-use paring chisel.

The shinogi usunomi is a serious tool for serious work that looks good while doing it.

YMHOS

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. May my square always lie to me if I lie to you.

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The Varieties of Japanese Chisels Part 12 – The Usunomi Paring Chisel (薄鑿)

Tsunekazu Nishioka

Our thoughts flow to our hands; our tools become as part of our bodies, the blade of our bodies.

Tsunekazu Nishioka, Temple Carpenter, Horyuji Temple Restoration, Nara Japan.

In the first post in this series, we examined the two main categories of Japanese chisels: the tatakinomi designed to be struck with hammer, and the tsukinomi used to pare wood without using a hammer. Beginning with this post we will shift our focus to several varieties of tsukinomi.

If you need to cut precise joints in wood, then you need both striking and paring chisels.

The most popular variety of tsukinomi is the mentori usunomi (面取り薄鑿)which translates to “beveled thin chisel.” The name is appropriate as the blade is long and thin and the neck gently tapered.

42mm Mentori Usunomi by Sukezane (Side View)
42mm Mentori Usunomi by Sukezane (Face View)
42mm Mentori Usunomi by Sukezane (Ura View)
42mm Mentori Usunomi by Sukezane (Face View)
24mm Mentori Usunomi by Sukezane (Ura View)

Description

Just as with oiirenomi, the blades of tsukinomi can be made with different profiles, such as the stiffer rectangular cross-section of the kakuuchi, or the more triangular cross-section of the shinogi usunomi.

The mentori usunomi has a streamlined cross-section similar to the mentori oiirenomi with two bevels ground into the right and left sides of the blade’s face, flowing over the shoulders and feathering into the neck.

An atsunomi or oiirenomi can pare joints, of course, but the steel crown and mushroomed wood fibers on the handle’s end make them uncomfortable for many hours at such jobs. More importantly, the blades and handles of these chisels are often too short to provide adequate angular control. In short, the usunomi is more comfortable to use, and pares wood more powerfully and more precisely.

Western paring chisels by comparison are even thinner and have longer blades than Japanese paring chisels. There can be no denying they do a fine job. But Japanese paring chisels like the usunomi have a few potential advantages worth considering.

The most significant advantage is that the steel cutting edges of Japanese paring chisels are much harder. The paring chisels our blacksmiths forge are around 65~66 HRc in hardness, whereas Western paring chisels are usually around 55 HRc. A Western style paring chisel with its thin blade of uniform steel hardened to 65 HRc would easily snap in half if stressed.

This extra-hard lamination is hand-forged by our blacksmith from Hitachi Metal’s Yasugi Shirogami No.1 steel (aka “White Label Steel”), an exceptionally pure high-carbon steel that makes possible an edge that stays sharper longer, with the result that, given the same number of sharpening opportunities and time in a given workday, a professional-grade usunomi will help you do more hours of high-quality work than a softer blade.

For craftsmen that use their tools to feed their families this higher-level of performance is not something to be sniffed at.

The second advantage of the Japanese paring chisel is their hollow-ground ura which makes it easier to maintain a flat bearing surface. If you haven’t used Japanese chisels, this claim may sound unlikely. But please recall that there are narrow lands surrounding the ura, all in the same plane, that create a flat bearing surface to guide the chisel.

Usage

This tool is well-suited to reaching into narrow mortises and other wood joints to clean and pare surfaces roughed out by axe, adze, saw and tatakinomi to precise tolerances.

It excels at trimming mortise side walls and end walls. And shaving tenon cheeks and shoulders to precise dimensions without causing spelching or cutting too deeply as shoulder planes are wont to do is a piece of cake.

In addition, the longer blade and flat face of the usunomi make it ideal for paring angles, such a 45° mitres, in combination with wooden guide blocks or jigs.

The usunomi may be struck with the heel of the hand, but never with a hammer or mallet. The slender neck, thin blade, and unreinforced handle will simply not accept such abuse gracefully.

Chisels intended to be struck with a hammer typically perform best with a cutting edge bevel of 27~30°. Any shallower and the hard steel at the cutting edge may chip instantly dulling the tool. However, the cutting edges of usunomi along with other tsukinomi are not normally subjected to the high stresses chisels motivated with hammers must endure, so the cutting efficiency can be increased by lowering the angle to 24° or so without creating problems, depending of course, on the wood you need to pare and the type of paring you intend. For instance, paring end grain may require a steeper angle than long grain.

If you have used long-bladed Western chisels hard for a few years, you will have no doubt experienced your chisel’s flat becoming somewhat rounded over after many sharpenings. This occurs because, for various reasons, the center portion of the blade’s flat is abraded at a slower rate when being sharpened than the blade’s perimeter, resulting in distortion regardless of whether you keep your stones perfectly flat or not.

Obviously, a chisel with a flat that is banana-shaped lengthwise and crosswise is not ideal for paring flat surfaces, but there is a bigger problem. Namely, it is simply more difficult and time-consuming  to create a sharp edge on a blade with a curved flat than one with a true flat. A flat like this begs for amateurish tricks using rulers, etc.. of the sort professionals would be embarrassed to use. A friend once scathingly described these techniques as “training wheels.” Oh my.

The ura on the Japanese chisel is specifically designed to deal with this shortcoming, and it does a great job of it.

30mm Unsunomi by Nagamitsu – View of Mitsuura
30mm Unsunomi by Nagamitsu – View of Face
30mm Unsunomi by Nagamitsu – Closeup of Mitsuura

The 30mm usunomi in the photo above has an ura with three hollow-ground areas instead of one. This detail is called a ” mitsuura” ミツ浦 meaning ”triple ura.” It has the advantage of providing a larger bearing surface than the standard ura does, one that is helpful when using wooden jigs for paring to precise angles, for instance. It also helps the ura index better when paring large surfaces, especially with chisel blades wider than 24mm.

Some people prefer chisels with the mitsuura detail for their appearance. I admit mitsuura look sexy, but I am not a fan of using this detail unless it is truly necessary because of the downsides I will not deal with in this already overlong post.

If I can liken the atsunomi to a shire horse, then the usunomi is a falcon. Both are beautiful powerful animals, but just as one wouldn’t use a draught horse to chase down a rabbit, or a peregrine to pull a plow, neither oiirenomi nor atsunomi are as effective as the usunomi for paring and cleaning joints.

A Shire Horse and His Little Friend. Stout, heavy and strong is good for some jobs, but…
Slim, light, fast and sharp is better for others.

The usunomi is one of those tools that is a pleasure to use.

Among woodworking tools, the usunomi is special: as it becomes part of your hand, you will discover that neither the blade nor your hand but your mind is shaping the wood.

YMHOS

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 bird of paradise nest in my hat.

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 a shire horse polish his hooves on my back.

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The Varieties of Japanese Chisels Part 11 – The Tsuba Nomi Guard Chisel (鍔鑿)

“The beginning of wisdom is to call things by their proper name.”

Confucius

The “Tsuba” in Tsuba Nomi is the Chinese character 鍔 which means “guard” as in a sword or knife guard.

Two nubs attached to opposing sides of the blade just below the handle look like the guard for a knife or sword. This chisel is driven with a hammer to quickly create a pilot hole for nails or screws. The blade becomes tightly wedged into the wood, but by striking up on these projections with a steel hammer, the blade can be extracted.

This unique chisel comes with blades with round, square, or rectangular cross-sections.

Square and rectagular blades usually have a chisel-point beveled on two sides, but sometimes are beveled on just one side. Round blades may have simple pointed ends, but sometimes they have short triple tines to drive the crushed wood fibers into the hole.

While this chisel severs the wood fibres, unlike an auger, drill, or gimlet, it does not remove material from the hole. The ends of the severed fibers are angled down into the hole, and over time and exposure to humidity and water, will partially swell back to their original shape locking nails in tightly.

This chisel is still used in the wooden shipbuilding industry, but other than that sees very little practical use nowadays. I own one but have have never used it in anger.

A Double-tsuba Nomi
Hole made by a Tsuba Nomi with a forged nail partially inserted. Used to to edge-join boards, this method is typical in traditional Japanese wooden shipbuilding
Far Left: Double Tsuba Nomi. Center: Single Tsuba Nomi. Far right: Strike up on the blade’s “guard” to extract.

YMHOS

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If you have questions or would like to learn more about our tools, please 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, incompetent facebook, or troublesome Twitter and so won’t sell, share, or profitably “misplace” your information. How could it be otherwise?

The Varieties of Japanese Chisels Part 10 – The Sotomaru Nomi Incannel Gouge (外丸鑿)

“There is a great satisfaction in building good tools for other people to use.”

Freeman Dyson

This is the second and final post about the heavy-duty Japanese carving gouges.

The Sotomaru Nomi” 外丸鑿 is what is called an “Incannel Gouge” in the West. “Soto” 外 means “outside” or “external,” “maru” 丸 means “round,” and “nomi” 鑿 means “chisel.”  The name corresponds closely to the English language term for incannel gouges.

As with other Japanese chisels, the Solomaru nomi has a thin layer of high-carbon steel laminated to a softer low-carbon steel body with a neck and tang. They also have the ferrule which compresses the handle’s wood to keep the blade’s tang firmly attached to the handle and prevent the handle from splitting, and a crown to prevent the handle from cracking when struck with a steel hammer.  Unlike most Japanese chisels, however, they do not have a hollow-ground ura.

The cutting edges differ from their Western counterparts in that the bevel is a single, flat plane, instead of a curved surface. The advantage of this detail when sharpening would be difficult to overstate. The blade can be sharpened on a normal, flat sharpening stone without pesky slips, finger contortions, or heaven forfend, miniature die grinders.

APPLICATIONS

This is an unusual chisel outside Japan, but is indispensable for working round wood and bamboo used in Japan’s sukiya and teahouse construction traditions. Although this chisel has many advantages,  it will not waste wood as rapidly as the uchimaru chisel we looked at in the previous post. Its shape is more conducive to cutting precisely curved surfaces than its concave sisters.

The coped end of a post to beam tenon joint cut with a sotomaru nomi.
Notice also the “sewari” kerf cut into the post in this and the next photo. I will discuss this interesting detail more in a future post, God willing and the creek don’t rise.
A “Sukiya” style exposed structural frame in peeled cedar wood with coped mortise and tenon joints, the ideal application of the Sotomaru Gouge.
“Round Work” in peeled cedar wood

SONY DSC

The hard steel lamination in this chisel has more support than its brother the uchimaru gouge we looked at in the previous post, making it a bit tougher.

Sharpening is easier and quicker than other gouges because the bevel can be treated as a single flat plane. The area called the “flat” or “ura” on conventional chisels is convex so it can be worked on a flat stone eliminating entirely the need for those pesky grooved stones and slips.

The disadvantage is that the flat bevel/curved cutting edge cannot make clean stopped cuts against 90 degree surfaces. This shortcoming is easily dealt with, however, by making a few more passes.

The sotomaru nomi is perfect for fitting straight line curved surfaces in some situations because its convex surface can ride and index directly on the concave surface being shaped, whereas the more common concave gouge must be tilted at an angle on its axis to cut, with less precision.

Since this chisel can cut parallel to its axis, and does not need to be angled up from the surface being worked to cut, it can cut and carve in much tighter locations than standard gouges.

If you need to make curved cuts at 90° to the workpiece’s surface, as in the photos above, then this chisel is indispensable. I’m sure you can see why this chisel is a must-have for the elegant ” round work” the Japanese love so much.

Another advantage is that the sloped cutting edge can easily make undercuts, something their Western counterpart cannot do. This is an essential performance criteria for accomplishing a few traditional Japanese architectural details such as the edge detail in the beam nose shown in the photo below. Good luck cutting that with a standard gouge!

It’s always nice to have the right tool for the job at hand.

Standard sizes are 9mm, 12mm, 15mm, 18mm, 24mm, 30mm, 36mm, and 42mm.

YMHOS

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. May I gag on a hairball if I lie.

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The Varieties of Japanese Chisels Part 9 – The Uchimaru Nomi Gouge (内丸鑿)

Carving a wagatabon container using an uchimaru gouge

“A good tool improves the way you work. A great tool improves the way you think.”

Jeff Duntemann

The Uchimaru Nomi is a gouge, very much like those seen in the West

The name is composed of 3 Chinese characters (kanji): 内 pronounced “uchi “which means “ inside” or “interior,” 丸 pronounced “maru” which means “round,” and 鑿 “nomi” which means chisel.

This gouge has a blade very similar in cross section to its Western counterpart, but unlike Western gouges, it is made of laminated steel, has the combined tang and ferrule construction typical of Japanese chisels, and a crown to reinforce the handle and protect it from violent hammer blows. These are strong chisels used by carpenters to carve large-scale architectural components, and sculptors.

They come in different sizes and sweeps, although not as many as the Swiss make. Some are the size of typical oiirenomi bench chisels; others are the size of the larger heavy-duty atsunomi.


As you can see, these blades are are not hollow-ground.

The relatively hard layer of steel which forms the cutting edge is often subjected to more lateral forces when carving than their straight-bladed cousins, and are sometimes damaged as a result. Professional carvers will hold the thin cutting edge over a small candle flame to reduce the hardness over a small area to reduce this tendency. I’m not recommending this practice, just conveying information.

The technique used for sharpening Japanese gouges is identical to their Western counterparts. To sharpen the outside bevel, typically one will use dedicated sharpening stones with grooves worn into them that are slightly greater than or equal to the radius of the gouge. One removes the burr and polishes the inside curve by using a short stone with a radiused edge.

A piece of leather charged with polishing compound can be used to put a final polish to the bevel. One can also bend this piece of leather to polish the gouge’s inside surface. Easy peezy.

Standard sizes are 9mm, 12mm, 15mm, 18mm, 24mm, 30mm, 36mm, and 42mm.

There are also uchimaru gouges made as paring chisels, with longer blades and handles, slimmer necks, and without crowns.

If you need a gouge that that can hog a lot of wood, will take an exceptionally sharp edge and will maintain it a long time, then this is a tool you should consider.

In the next post, we will look at a different type of gouge, one you may not have seen before.

YMHOS

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. May I gag on a hairball if I lie.

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