The Japanese Gennou & Handle Part 9 – Mass-produced Head vs. Hand-forged Head

A “Classic” style 150monme/ 556gm/ 20oz gennou head hand-forged by Hasegawa Kosaburo

The gentle reader will never, never know what a consummate ass he can become until he goes abroad. I speak now, of course, in the supposition that the gentle reader has not been abroad, and therefore is not already a consummate ass. If the case be otherwise, I beg his pardon and extend to him the cordial hand of fellowship and call him brother. I shall always delight to meet an ass after my own heart when I have finished my travels.
Mark Twain, The Innocents Abroad

In the previous post in this series we discussed the various styles of gennou heads you might consider when planning a custom-made gennou that fits your body perfectly, as well as the range of weights for each application.

While one has few options besides either using a mass-produced head or making one yourself nowadays, in Japan there are still a few blacksmiths that specialize in hand-forging high-quality gennou hammer heads. In this post we will compare mass-produced heads and hand-forged heads to help you make an informed decision.

Comparing Mass-produced Heads to High-quality Hand-forged Heads

When selecting a gennou head you have the choice of a mass-produced gennou (usually with a handle attached) or a handmade gennou head without a handle, if you can find one. Lets examine the differences.

A modern-style 200monme/750gm gennou head hand-forged by Aida Hiroki. The lines are straightish, the skin is plain forge oxide, and each end has a teeny tiny, almost no, polished band.

A “Modern” style 100monme/375gm gennou head from the Kohiyama factory in Niigata prefecture (old-stock), definitely the upper-level of factory gennou heads, but not in the same class as hand-forged heads by Kosaburo or Hiroki shown above, but still useable. “Munehomare” brand. It tapers from both faces towards the waist, the chamfers further accenting the taper. An appealing shape.

A mass-produced “Modern” style 80monme/300gm gennou head from the Miyaguchi factory in Niigata prefecture (old-stock), This is a typical factory gennou head, perhaps better than most. While the eye is properly centered, the walls are far from clean, and the overall quality is nothing to brag about. Definitely not an heirloom tool.

Mass-produced genno are readily available, relatively inexpensive and for the most part, entirely useable. However, as with any product, it is wise to inspect a gennou carefully before purchasing it, as discussed in a previous post in this series, or to at least buy from a retailer with a solid return policy. When purchasing any gennou, check to make sure the eye is centered in the head and not skewed.

The practical advantages of a hand-forged gennou hammer head over a mass-produced factory head are as follows:

Proper differential hardness;
Precise eye placement;
Uniform interior dimensions of the eye, resulting in time saved and aggravation avoided when fitting/refitting a handle;
Faces are square with the long axis of the head;
Improved Performance due to more uniform distribution of mass providing improved stability during the swing with fewer wiggles, more solid strikes, and fewer off-center hits.
Unique appearance and pride of ownership.

Let’s examine these points in more detail next.

Heat Treatment

Most Gentle Readers will have never given this matter any thought, but the quality of the heat treatment matters… a lot. This is a chemical/crystalline property impossible to confirm long-distance, so we must rely on the manufacturer, be it factory or blacksmith, to get right. Therefore, the manufacturer’s QC reputation as well as the retailer’s guarantee also matters.

A good head will be hard at the faces, becoming gradually softer towards the the eye, certainly softer than a file, to make the head “tougher,” using the materials engineering term, and to reduce resonant harmonic vibrations. If you have used hammers with uniformly hard heads and integral steel handles you have felt this tiring vibration before.

The faces must be hard, around 50~55Rc, to prevent deformation, but not so hard the hammer will chip or crack. You may think that wooden chisel handles could not deform a steel hammer face, but if the striking faces are not properly hardened, they will mushroom sure as eggses is eggses, something your humble servant learned when he made a gennou head for himself from unhardened octagonal steel bar stock back when dinosaurs roamed the earth.

It’s interesting to note that the handle I made in days of yore was straight, unlike the handles your humble servant currently advocates, and that lower 1/3rd of the face (closest to the hand) mushroomed, while the upper 2/3rds did not deform at all. Curious…. This was the first time I really noticed that the head of hammer with a straight handle attached perpendicular to the head’s centerline tends to hit the chisel/nail cocked and not in-line with the long axis of the chisel/nail. I also realized that the direction of flow of this steel indicated a lot of energy was being wasted by my straight handle. I hope you can see why the solution the anaya carpenters of Japan developed so long ago resonated with me so strongly.

But what happens if the heat treatment results in a head that is too hard? In this case, while the head and faces may not deform, the face may chip and the entire head may fracture, sometimes even causing embarrassing leakage of sticky red stuff (or at least that’s what the product liability lawyers assert).

A word to the wise: always use properly heat-treated hammers and wear safety glasses when pounding nails, mixing acid, or writing your name on your forehead with ballpoint pen after losing a tequila shot contest.

Precision of the Eye

Gentle Readers may think it passing strange that your most humble and obedient servant is seemingly fixated on the precision of something as boring as the hole in a hammer’s head. Rest assured, this concern is not a fever dream resulting from an obsessive/compulsive over-analysis of negative space, but was born of bitter experience. My new therapist concurs.

Of all handtools, the hammer is one of the simplest. But is also the one that moves the fastest and is most influenced by dynamic physics. Things like concentricity, center of gravity, and moment of inertia make a difference to an object moving this quickly, then suddenly slowed by an impact with a chisel or nail, and then returned to battery for another blow faster than you can say “ouch.” Negative spaces like holes influence the physics, and therefore the stability, of hammer heads. Don’t make me inflict you with differential equations, just take my word the hole needs to be centered, not skewed, and of uniform size or the hammer will be skittish resulting in twisted mortise holes, bent nails, and maybe even smashed thumbs.

Another advantage of a well-made gennou head is that its eye will have uniform interior dimensions. We talked about this in an earlier post. In summary, all four walls will be straight, clean, flat, free of wind, parallel and square to each other. This matters because a sloppy eye will not apply uniform pressure on the handle’s tenon, ensuring it will come loose sooner than later. In addition, this uneven pressure may also induce unwanted vibrations in the handle.

If a gennou head has a sloppy eye, it needs to be trued, a task that is difficult to accomplish using files. Depending on the degree of error, correcting the inside walls of that tiny hole in a steel head with skinny files can be frustrating work and may even help your own therapist buy that new bimini top he wants for his fishing boat. You see, most people make the problems worse the first time they try to correct them. I know I did. If you count your time worth anything, the extra cost of a precision eye is money well spent, and certainly cheaper than a Rolex for your therapist’s girlfriend.

This image has an empty alt attribute; its file name is kosaburotansetsugennou.jpg — A “Modern”style hand-forged gennou head by Hasegawa Kosaburo. This head is of antique construction with high-carbon steel wafers forge-welded to both striking faces of the softish iron body. Prior to the importation from Europe of cheap steel to Japan, all gennou had this laminated construction. I have been using this head for over 35 years. I think this is its third handle.

This image has an empty alt attribute; its file name is gennou.jpg — A standard hardware store mass-produced gennou made by a large corporation and sold everywhere in Japan. The eye is sloppy, so the head is secured with steel wedges. The handle is tapered towards the eye to compensate for and conceal dimensional irregularities. Of course, this hammer can hit stuff just fine, but it will never feel right, the head will loosen much sooner than later, and it will be impossible to adequately repair. A decidedly unprofessional, disposable tool.

Precision of the Face

Let’s move on to item 4 “Faces are square with the long axis of the head.” The striking faces of mass-produced hammer heads are often not square with the head’s axis (i.e. manufactured 90˚ to to the head’s longitudinal axis) resulting most obviously in bent nails, but the less obvious consequence is that energy we intended to transmit directly to the chisel and into the workpiece ends up being wasted as heat and violent movement of the chisel out of alignment. It also wastes time and undermines the user’s confidence, once again providing a windfall to head doctors everywhere. A precisely manufactured face square to the tool’s centerline will yield better static performance and more precise chisel work and nail bashing than a mass-produced head.

A “Yamakichi” style 80monme/312gm gennou head hand-forged by Hiroki Aida

The hammer that is stable during the swing and makes a solid impact exactly where you aimed it without producing strange vibrations or wasting energy will help you make every strike with confidence and greater control, and will make your woodworking more enjoyable and profitable. Not insignificant benefits.

Improved Dynamic Performance

In addition to the advantages described in the previous paragraph, a hand-forged head, if made correctly, will be more stable during the swing, and wiggle less upon impact because its mass is more uniformly distributed. This means fewer misses and more energy transmission on impact. And that’s the whole purpose of a hammer, right?

A hammer made using a good head and a handle made to fit both that head and your body will perform better than any tool you have experienced before. You won’t need to look when you pick it up to tell which face (or claw/vs face) is oriented towards the nail/chisel because your fingers will know instantly. The handle will fit your hand perfectly without slipping or causing blisters or needing to be “choked-up on.” You will be able to sense beforehand exactly where the center of the hammer’s face will strike, and will be able to hit the target dead-center and squarely even with your eyes closed.

Appearance and Pride of Ownership

And finally, let’s examine the more ephemeral item 5: “Unique appearance and pride of ownership.” I have mentioned it elsewhere before, but it is a fact that, no matter how much they may deny it, humans are competitive beasties in all endeavors.

As a day job your humble servant manages construction projects in Japan and spends a lot of time inspecting jobsites, meeting with construction companies and speaking with craftsmen. Indeed, there was a time when I was labor instead of management on construction jobsites, so I have enough experience to know that, while some professional woodworkers may not read fashion magazines with titles like “Amazing New Toolbag Design that Will Lift and Shape Your Butt” during coffee breaks, or wear sleek, handmade calf-skin steel-toe Italian footwear during the workday, they are conscious of their personal performance, and the performance of their tools, in comparison to those of their peers. It’s a guy thing, something women think they understand because they have similar tendencies in other areas, but rarely do. This performance is difficult to ascertain unless one is working side by side with one’s peers, so it is human nature to make indirect judgements about performance by observing the quality and condition of a fellow worker’s tools.

Of course, one casually notices the brand of chisel or plane a fellow craftsman is using. Next, if it can be done without being rude (sometimes a difficult thing to accomplish), one examines the fellow workman’s tool’s cutting edge and its sharpness because this tells much about his character and skill (chisels are terrible gossips, you see). Such a close examination may not be possible, but one can usually examine the finish left by his plane and crispness and precision of his chisel cuts.

But more than plane or chisel, the tool that is always visible to others during the workday is the craftsman’s hammer comprised of the head forged by the blacksmith, and the handle made by the craftsman himself. The quality of this combination tells Japanese craftsmen much about the man that owns and uses the tool. A hand-forged head by Kosaburo or Hiroki with a graceful, professional-grade handle made by the owner, even if it is dinged through years of hard use, will be noticed by those with eyes to see for decades, even generations.

Among the Japanese professional woodworkers your humble servant knows well, most of whom ceased getting older long ago, a highly-decorated expensive gennou head is thought to be a gaudy, obvious plea for attention, and in poor taste, like wearing a purple sequined silk suit and Jimmy Choo 8″ gold lame stilettos to the hardware store (best saved for the New Years party anyway, you sexy beast). A plain head by Hiroki or Kosaburo, on the other hand, is understated tasteful evidence of a serious craftsman that appreciates tradition and places quality first. Very much a wabi sabi kinda thing.

And finally, a quality hand-forged head is a lifetime tool, one that won’t wear out or break. The handle may be damaged and wear out over time and need to be replaced, but such wear and tear is unavoidable if the tool is actually used, like a good pair of workboots. But the handle made for a quality head will last longer and be much much easier and quicker to replace. To the professional focused on turning his time into money, this is not an insignificant consideration.

A mass-produced factory head, by comparison, simply won’t work as well. It is of course neither high-quality, unique, nor a lifetime heirloom tool. It isn’t pleasing to the owner’s eye nor impressive to his fellow workers. It is a consumable, expedient tool, the sort of thing a craftsman does not want himself to become.

Conclusion

A high-quality head combined with a handle that fits your body will accomplish more work more precisely with less mental concentration and physical effort. It will become a lifetime friend and a source of satisfaction boosting your confidence. It will be relatively easy to make replacement handles for during your lifetime, and those handles will stay tighter longer. It will tell those who see it that you are serious, no-nonsense craftsman who understands true quality and prefers understated elegance.

If you take pride in your tools, appreciate heirloom value, don’t want to waste time trying to rework sow’s ears into silk purses that smell piggy, and are not inclined to invite psychiatrists to rummage around in your head, then a hand-forged gennou head is worth owning, in the opinion of your most humble and obedient servant.

In the next post in this swashbuckling adventure on the high seas we will try to dispel some rumors about laminated gennou heads.

YMHOS

My newest safety shoes. I must say they go really well with my dual-reel safety harness! What do you think about the steel-toe safety shoes below? Too severe?

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Toolchests Part 8 – Under the Lid

Even the smallest person can change the course of history.
Lady Galadriel – The Lord of the Rings

In previous posts in this series about toolchests, and your humble servant’s toolchest in particular, we looked at how the design was guided by performance criteria such as portability, tie-down and lifting, and pixie infestation prevention. In this post we will examine one solution to another performance criteria. Perhaps the solutions in this article will help you solidify your storage requirements.

Inside the Lid

Key Performance Criteria No.4 defined in Part 5 of this series is as follows:

Tool Access: Tools used frequently to be quick to locate and easy to remove and replace without bending, kneeling, or shifting trays around.

The solution I selected was to mount many of the tools I use most frequently inside the lid where they are in clear view and quickly accessible. This technique is one seen in historical examples, but as always, I wanted to do things a little bigger, a little better.

Alas, unbeknownst to me I had fallen prey to a sophistry that has afflicted many, indeed one that has destroyed entire civilizations and can be summarized as: “ if a little bit is good then too much must be excellent.”

I began the planning of this space with visions of Mr. Studley’s famous toolchest dancing in my head. The image in my mind was mahvelous dahling, simply mahvelous, but the conceptual drawing was only good. While I was distracted by my dreams, reality snuck up behind me, shot me in the head and dumped my virtual body in the river. The water was cold!

After a refreshing swim I realized my plan was too dense, too inflexible, too expensive, and most importantly, violated the unwritten performance criteria common to most human endeavors: “It must be finished in my lifetime.”

The compromise I arrived at is shown in this post. It is not perfect. You should not emulate it. But it is the fruit of trial and lots of error over many years and it works reliably.

A view of the inside of the toolchest’s lid with all the tools in residence. Please also notice the 5 heavy brass butt hinges, the sealing lip around the inside edge of the lid, and the brass chain to keep the lid from flopping open. The unusual wooden tool mounted nearly in the center is an unused, hand-carved Japanese inkpot called a “sumitsubo,” an excellent tool for snapping straight lines on wood. Its purpose here is purely decorative. My daily-use sumitsubo is the blue plastic widget located below the wooden sumitsubo; far more practical but not as traditional, sculptural or as propitious.

An obvious problem with mounting tools inside a lid is their rebellious desire to drop to the bottom of the chest when the lid is closed, especially if the petty pernicious pixies that sometimes skulk in the shadows of my workshop lend a claw.

To deal with this mischievous propensity, each tool’s mounting mechanism must retain the tool securely in place while the lid is opened, closed, and even while the toolchest is being moved around. At the same time, the mounting mechanism must be simple and quick to operate. This combination of security and speed is not as easy to accomplish as Gentle Reader might imagine because, well, tools can be naughty, and gravity is not our friend when the lid is closed. And pixies.

In the center of the picture is a favorite old Japanese screwdriver with a bulbous handle made from keyaki (zelkova wood). Behind it are mounted two Yankee screwdrivers of different lengths along with driver and Japanese-style gimlet bits. To the left, most of the wooden sumitsubo, secured to its mounting board by a leather thong, is visible. Under it you can see the fire-damaged end of the handle of a Millers Falls eggbeater. To the right is a set of expensive but dismal-quality oiirenomi (since replaced) and the handles of gennou hammers. Bits for the brace mounted behind the hammer handles are stored in the space behind the chisel blades. The sealing lip attached to the inside of the lid is visible just above the brass butt hinge. This is simply nailed in place to be easily replaced if damaged, but that has not been necessary yet.

So let’s examine the tools mounted inside the lid and how they are secured.

The upper third of the lid is dominated by two full-width parallel boards secured to both sides of the lid. These two boards have edge lips and matching notches. The left side holds 7 marking gauges of various lengths and types. Four of them are dual-blade mortise gauges (kamakebiki) made by Kinshiro. After placing a marking gauge in its designated set of slots, it is secured by extending the tool’s beam or blade upwards and locking it in place with its own adjusting screw. This mounting method has been entirely successful.

The right hand side of these parallel boards holds 8 hammers (gennou). The back-side of each notch and the surrounding lip is shaped to fit a specific hammer, and super-magnets help hold each hammer’s steel head in place.

The handles of the chisels mounted below also help to retain the hammers, as you can see from the photo. This is not a perfect solution, but it has not let me down so far.

The tools stored in the lid’s right-hand side spread out for your inspection. The 11 chisels are not shown.

The 11 chisels on the right side are held in place by friction between the chisel’s cone-shaped ferrules and the closely-fitted wood notches, and stay in place even when the lid is closed. But vibration can become a problem if I need to move the chest over a rough surface with the lid closed, so I wrap a rubber bungee cord around the chisel’s handles to keep them in their slots during jiggly transport.

The chisel’s cutting edges are oriented downward when the lid is open, close to the lid’s side (below) so that there is little danger of snagging a finger or wrist on the extremely sharp edges. I strongly dislike getting red sticky stuff all over my tools, and accordingly I disdain any storage system that leaves sharp cutting edges exposed.

Whatever chisel storage solution selected, I strongly urge Gentle Reader to ensure there is no opportunity for chisels to express their peckish nature for three reasons: First, 10 fingers are better than 9 (just ask Frodo); Second, red sticky stuff promotes rust; and Third, Murphy always has the last laugh. I promise you won’t like whatever gives that bloody bastard the giggles when chisels are involved.

A 10-pc set of Kiyohisa oiirenomi with white oak handles mounted inside the lid. I was deeply dissatisfied with the poor quality of these expensive chisels and have since replaced them with the higher-quality but much less expensive set with red oak handles shown in the next photo. A sokozarai chisel with a red oak handle is mounted to the far right of the row. An antique brace with rosewood fittings, as well as an old Starrett protractor head are mounted behind the chisels and gennou hammer handles

Behind the chisel and hammer handles, you can see my Starrett protractor head, and my father’s old Stanley brace with rosewood fittings. Bits are placed in tool wraps and stored in a compartment behind the chisel blades. Not easy to get at. I have thought about combining the chisel rack into a drawer to hold the bits, but have not done anything yet because I’m not sure it would be an improvement.

The tools mounted in the lid’s left-hand side are removed and displayed for your inspection. The zelkova wood sumitsubo hand-carved in the lucky turtle and stork pattern can be seen in profile with its ebony karuko needle and bamboo sumisashi marking stick below. The black plastic bottle with the blue and white lid at the far right contains ink for the sumitsubo.

On the left side, a Starrett 92 divider and two spring dividers are secured by a block screwed to the far left sidewall. Chastely closing the divider’s legs together pinches a screw head locking them securely in place. If you don’t already own a Starrett 92, you need to get one.

In this photo the sumitsubo is front and center. The tails of 6 marking gauges, 4 of which are dual-blade units by Kinshiro, can be seen in the rack above.

Behind the dividers, there are several steel rulers and a bevel gauge secured by a hook on top and retained by the Starrett 92’s arm. In the center are mounted 3 Matsui Precision stainless steel squares, a Starrett combo square, a Starrett adjustable mini square, and a thickness caliper.

I also mounted an unused hand-carved Zelkova-wood Japanese inkline/inkpot (墨壷 sumitsubo) with silk wadding in a central position of honor. While this is a practical tool, I mounted it there just as decoration and for good luck, as you can tell because the line is still blue and the silk wadding is still white. I have a more convenient sealed Shinwa-brand plastic sumitsubo stored in the top tray I use when I need to snap a line.

At the bottom of the lid I mounted an old Millers Falls eggbeater drill. I don’t recall the model number, but I purchased it used in Delaware, Ohio many moons ago. The cap on the handle was damaged by fire sometime before I bought it. It’s a handy a little guy, but nothing special.

On the left side of the center vertical divider are mounted 2 Yankee spiral screwdrivers, bits and gimlet blades, as well as an antique Japanese screwdriver with a polished steel shaft and a bulbous Zelkova wood handle. I am irrationally fond of this old tool.

I have tried different arrangements for mounting tools inside the lid over the years, and I will continue to improve it because I am confident the solution shown is not the best possible arrangement. It’s a difficult planning problem for two reasons. First, the tools in the lid are the most easily accessible and therefore must be ones I need all the time. Assigning priority and ease of access seems as easy as falling off a greasy log, but it isn’t. The Studley solutions to storing tools are amazing, but not really practical. Second, I need to be able to remove and store these tools quickly, but at the same time, they can’t be so heavy or so difficult to secure they fall out when the lid closes or opens. Once again, the conflict between safety and security is tricky to resolve.

Regarding priority, marking gauges and other layout tools see the highest frequency of use, followed by chisels, hammers, drills and screwdrivers. This priority is reflected in their location inside the lid, as you can see.

I don’t use the protractor head, brace or bits very often, so they are assigned a lower priority and reside behind the hammers and chisels. It takes time to remove them, but on the other hand, they would always be in the way if placed in the trays, which is more valuable real estate, so this is their home.

To hold the lid open and keep it from flopping back, I installed a brass toilet tank chain on the left side, and boxed out a space so it doesn’t hang up on tools. When the lid is closed, it automatically lays alongside the top tray. This chain was inexpensive, it’s strong, it will never rust, and it has never caused me a second of grief.

Well, that’s all for this post. Next time we’ll look at the trays. There will be planes. Oh joy!

YMHOS

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The Japanese Floor Workbench (Atedai 当て台) by Dominic Campbell – Part 2

Good hip and knee flexibility is needed when working on the floor, but tabi socks are optional! Credit: D.Campbell

When a work lifts your spirits and inspires bold and noble thoughts in you, do not look for any other standard to judge by: the work is good, the product of a master craftsman.
Jean de la Bruyere

Introduction

Gentle Reader, welcome to this second installment in my series of articles about the Japanese floor workbench called the “Atedai.” In Part 1 we looked at some of the design considerations and construction techniques involved in making this tool. In this presentation we will get to the fun part of putting it to use.

These workbenches, as I hope you will see, are incredibly versatile tools that can be used in endless ways. My objective in this article is to show you a number of those methods, some traditional and some less so, and inspire you to maybe give it a go yourself.

I will use examples from my own work, as well as examples from master craftsmen (including a few National Living Treasures of Japan) who have completed rigorous apprenticeships and used atedai professionally much longer than I ever will.

I have not received any direct training in this method of working but have ‘stolen’ many ideas and methods (lit. “Gijutsu wo nusumu” 技術を盗む) through observation and practice of their techniques.

This is the way traditional apprenticeships run in Japan – the master seldom gives direct instructions and entertains few questions, yet the apprentice is expected to learn everything – through observation and practice – and is thus said to “steal” his master’s techniques. Only in my case, my teachers are Stan, books, the internet, and videos!

I will use a fair number of pictures and video links in this blog, as they will show much more nuance than words can about how master craftsmen use their Atedai.

Disclaimer

If you live in a ‘chair culture’ and are just starting to work lower to the ground, then this may be the first time you have sat cross-legged on the floor since school. Take it easy! Go slow, improve your flexibility gradually and your knees will thank you. This style of woodworking is physical, and you must orient your whole body with the work to be efficient, and safe, which at first can cause some aches and pains. Bear with it – the results will be worth a little suffering!

If the floor is out of the question, don’t despair! There are a number of ways to use an Atedai either sitting on a stool or standing, which we will explore in this article as well.

With that said, let’s begin!

When placed low on the floor, an atedai workbench is much, much bigger and more stable than a standard table-style workbench. Using a woven-reed goza mat, or other soft floor covering, you can convert any reasonable space into an efficient work area in a couple of minutes. The goza makes it easy to spread your tools around you within easy reach to keep the work going quickly. It also makes cleanup of woodchips, shavings and sawdust easy. And of course there’s no worry about tools being damaged by rolling off the workbench. Win-Win. Credit: D. Campbell

Sawing

Sawing using an atedai falls mainly into two categories – rough sawing for stock preparation, and precision sawing for finer work/joinery.

Rough sawing doesn’t differ much from using low sawhorses… you lay your work flat on the bench, making sure to hang it over the side, or off the far end of the bench, and use your foot to stabilize the board while your hands work the saw. This is very quick and accurate methodology, one that doesn’t require the large, bulky, difficult-to-store sawhorses typically used in the Western woodworking tradition, but it is dependent on using Japanese saws.

Cross-cutting lumber using a Japanese pull-saw and an atedai. The craftsman in these videos is a well known “sashimono-shi” named Kimura Tadashi. Credit: Kotaro Tanaka

The process of rough sawing is the same, more or less, as when using low sawhorses. Using one’s feet to stabilize the workpiece helps significantly. You can also stand with both feet on the stock, which can be very useful when making big rip cuts in large stock.

Fine sawing can be slightly ‘fussier’ in getting the work where it needs to be, and can depend on the kind of joint you are cutting. That said, it often helps to prop the work up somehow, particularly when ripping. This can be accomplished by leaning it vertically against the end of the Atedai, or laying the work flat on the bench (a clamp can help here) and propping up the end of the Atedai – experiment and see what works for you. I have seen craftsmen using plane blocks to prop up the near end of the bench – an ingenious and elegant solution, yet maybe not as quick as just leaning it on the end…

Another famous sashimono-shi, Mogami Toyojirou, leaning the work vertically into the end of the atedai to raise it off the bench to saw hidden mitred dovetails, a classical joint. Credit: Kotaro Tanaka

Note the size of the stops on Mr. Mogami’s atedai are much smaller than my own, and very much in the sashimono tradition.

Any cross cut, like the cutting of tenon shoulders, can be made off to the side of the bench or, if your stops are low enough, in the middle of the bench itself. I prefer to saw to one side, giving my arm room to move back and forward without having to shift position too much. You can also use shorter Western joinery saws here, by pushing the work into the stops, almost like a bench hook.

Planing

Planing at the Atedai is accomplished in only one or two positions… sitting down crossed legged, sometimes with one leg extended, or while on both knees. Give it a try and see what works best for you in your work.

You hold your plane in both hands, reach and pull. Simple.

In my experience, I have found that kneeling on both knees works best for powerful roughing strokes, because I can make use my upper body weight to press down on the workpiece while making powerful, controlled cutting strokes with the plane. Alternately, planing while sitting with one leg extended works best for me for finish planing. YMMV – experiment and find what works for you.

For really long stock you can, in theory, lunge forward with one leg and rock back with the planing stroke, but that still has a length limit (not to mention the need for very strong leg and back muscles) and standing up really has all the advantage in this situation. Traditionally, craftspeople such as Tategu-shi, joiners who specialize in doors and shoji, have a dedicated planing beam or bench on legs set up in their workshop, used standing, for longer stock preparation, and use their Atedai used for mortising and other smaller tasks.

Ono Showasai planing on both knees. Credit: 木工芸-大野昭和齋の指物わざ

Mr. Mogami planing with one leg extended. Credit:Kotaro Tanaka

“What about my Baileys?!” I hear you cry.

Fear not, Gentle Reader, for you can still use Western planes… both on the normal push stroke, as well as the pull… by adopting this work style. I often use No.5 and No.7 planes for initial rough stock preparation, and both can be used well low-down, although it must be said not quite as well as Japanese planes. To push I often kneel to the side, or sit on the work and push towards the stops. Maybe not elegant, but still good enough for me – either way, no one is watching, except maybe Master Sprocket, the neighbor’s cat, who meticulously supervises every step of my work!

Yes, you can use western planes on the floor. It’s maybe not as efficient without the use of your legs, but I have flattened tabletops on the floor with the help of a no. 5 and no. 7 plane. Have you tried pulling a western plane? It works surprisingly well! Just grab the knob with your left or right hand and place your other hand on the handle. Credit: D. Campbell

The honorable Master Sprocket come by for his daily inspection. He is a tough, but fair, task master that doesn’t judge my use of push planes at the low bench too harshly, so long as the work is completed on-time. Also instrumental in keeping the workshop pixies at bay. Credit: D. Campbell

Another way to use push planes is to stand the atedai on its side and clamp the workpiece to its face, which allows you to plane standing up… this can also be useful with Japanese planes when planing longer boards or when you just need to stretch your legs and rest your back.

By standing the atedai on its side, you can use push planes with ease. Remember to place the atedai on the side you don’t use to shoot with, in my case the left side. Credit: D. Campbell

Jigs for any number of planing tasks are used as much in the Japanese tradition as they are in the West for 45° and 90° angles and, except for being designed for the pull stroke, do not really differ. One jig, however that may be new to you is a rather simple, but incredibly effective, device helping to shoot long edges. It is simply a flat board with a stop, which elevates the board above the surface of the bench, allowing your plane to shoot the edge of a board. This is one of the reasons you will often see 2 stops rather than 1 long stop on the Atedai. One stop braces the shooting board and workpiece while the gap between the two stops allows the plane to pass through and finish the stroke.

Mr. Mogami planing the edge of this board with the help of a simple, but very useful, jig not often seen in Western woodworking. From the video linked to above. Credit:Kotaro Tanaka

Chisel Work

Just as when planing, there are a number of ways, and many more besides, to use chisels at an Atedai depending on the task at hand.

For mortising, and other similar tasks, a great way to hold the work is with your derrière. Yes, finally we come to the famous bum clamp. Sitting on your stock (while potentially uncomfortable on narrow or high stock) is one of the best ways to keep the work steady and both hands free for using tools while positioning yourself for efficient and safe work with your eye directly over the mortise to help ensure the chisel stays plumb. As we will see, this is also very effective while at a standing bench too.

The veritable bum clamp displayed **here** by Mr. Toshio Odate. Note the cushion – a long day mortising without it isn’t much fun – and the nihon mukoumachi nomi in his hand, a specialized dual-blade chisel for cutting double mortices. Credit: Popular Woodworking

Hollowing work, like that used in kurimono carving, is often performed while sitting to the side of the bench directing all the force into the stop, and keeping the work steady. Be warned here, keep a mental note of where your left knee is in relation to your chisel! In this position it’s easy to make powerful horizontal hammer blows, and the last thing you want is a chisel jumping out of the cut into your knee.

In this photo I am sitting at the side of the bench performing the heavy chisel work of hollowing. Impact forces are directed towards the stops, which is why I installed larger than average stops on my bench. In my previous post, I mentioned leaving the underside of my bench untouched – you can see the irregular thickness where the leg is dovetailed into the top. Credit: D. Campbell

Akira Murayama hollowing a tray made of keyaki wood (zelkova). Any similarity to my own work is purely coincidental! 😉 Note – in all these pictures, and videos to follow, you will see the oil pot is never far away. This is, IMHO, *the* most important tool you can own – I implore you to make one!

The final ‘standard’ chiselling position is at the end of the Atedai, often using your foot to stabilize the work piece, although clamps may also be used. This allows for quick repositioning of the workpiece, if needed, and holds the work solidly enough for the work at hand (foot?). As you tend to chisel more or less vertically in this position, your foot isn’t in much danger, but it still pays to be cognizant of the potential risk at all times.

Mr. Nakadai Zuishin using his foot to steady the workpiece. Note, you will often see the use of tightly-woven cotton tabi socks by craftsmen of all trades in Japan. While traditional, I also use them because normal cotton socks are like sawdust magnets, and my wife is fed up with hoovering the house! It also helps keep the stock clean, especially important in the finishing stages.

This is number 3 in a 9 video series of Mr. Nakadai, designated one of Japan’s National Living Treasures, making a beautiful serving bowl for the tea ceremony from pauwlonia wood. You can view the entire playlist on YouTube at this link.

Standing & Sitting

So far, we have looked at using the Atedai while it is resting on the floor, but there are a number of other ways to use it if your knees say “no”, or if you just prefer to work while standing up.

A great way to integrate the planing bench into your normal workflow is to have a slightly smaller Atedai for use on top of your normal workbench. This can be a great option if you use a mixture of western and Japanese planes, and can give you the best of both worlds. If you dimension it so you can place the Atedai under your table workbench when not in use, you can quickly and easily pull it out when needed.

A smaller atedai placed on top of a table workbenchj for planing while standing. Although smaller in dimensions, construction is the same. Note the slight angle towards the stopped end, which some prefer. Credit: Kiyoto Tanaka, a superb luthier https://www.youtube.com/watch?v=PQVqu3GRbQ0

If you prefer to sit on a stool when you work, an atedai placed on a lower table is the perfect solution. Credit: kougeihinjp https://www.youtube.com/watch?v=-Gkt3yrdZVw

By placing the Atedai on sawhorses, you will have a versatile, and mobile workbench which, with some practice, will do everything you ask of it. Carpenters in the field will often use a bench similar to this, made with materials on site, although they can sometimes be rather quick and dirty affairs.

In the photo above, Mr. Makoto Imai, a highly skilled carpenter, is using a similar set up, which was immortalised in ‘The Workbench Book’ by Scott Landis. The stop here is just a screw, which is all you need for most planing operations – although care must be taken if you don’t want to mark the end grain. I love the simplicity of this set up, and find Makoto’s work truly inspiring. Credit: Daiku Dojo http://www.daikudojo.org/Archive/20070414_tfgwc_asilomar_makoto_imai_demo/

While easier on the body in some respects, the lack of vises (Editor’s note: “virtually free of sin”) still means these workbenches require good flexibility and the use of body clamps. There is no escaping the fact that Japanese woodworking can be very physical. With that said, due to the need to lift your knee/leg up to, or to sit on, this kind of bench I have found the work surface needs to be slightly lower than your normal Western bench – for me about the height of my downward facing palm, with my arm by my side.

The traditional knee clamp holding the workpiece in place while mortising. This may look ungainly, but is surprisingly comfortable, and is a really quick and efficient way to work. This was my previous ‘workbench’, which I used a lot before I got started in kurimono carving, and needed something more stable under heavy horizontal chiselling. Credit: D. Campbell

Using your bench, to build your bench. This picture was taken as I was making the Atedai… with no stops and no feet I could still make the stops, cut out the sliding dovetails, and make the legs. No vise? No problem! That is the beauty of Japanese tools, for me. A heavy beam will stay put under its own weight, but legs, dowels, or similar, underneath will definitely stop it from shifting. The addition of a diagonal brace between sawhorses creates an incredibly stable working surface. Credit: D. Campbell

Miscellaneous

As you have no doubt seen, the potential ways to use the Atedai are incredibly varied. In this section I will outline some interesting techniques and ideas that may help show you just what is possible with these benches, or at least give some food for thought.

Firstly, using low sawhorses of the same height as your Atedai is a great way to extend the length or width of the work surface, and is a great solution for things like doors or shoji frames. It can also be incredibly useful if combined with, for example, a chop saw set at the same height.

Combined with low sawhorses of the same height, you can extend the workbench surface lengthwise or sideways. A great solution when working with things like doors, or longer sections of stock. Credit: D. Campbell

Next, in a real blurring of east and west, you can put dog holes in your workbench – similarly spaced as you would on a normal workbench, for use of bench dogs, and hold fasts (Veritas make a lovely version which you can hand tighten). This can really add some versatility to your bench.

These holes will also give you an alternative to the ‘foot clamp’. By making a piece of wood with a hole drilled about ⅓ of the way in from one end, and a bolt passing through it into a dog hole (no need to attach a nut to the other end), you can create a foot-operated lever to press a workpiece into your stop, holding it very securely. The picture below shows Mr. Inomoto using this ingenious tool with his atedai

Isao Inomoto making one of his famous plane blocks using an ingenious ‘foot clamp’. A series of holes along his bench allow for different size blocks. Credit: Daiku Dojo http://www.daikudojo.org/Archive/20071028_inomoto_dai_making_seminar_day2_kiwa_kanna/

Conclusion

So, there you have it, a whistle stop tour of how to use an atedai. As you can see, the atedai is hugely versatile, and can offer all woodworkers, especially users of Japanese tools, a great way of working.

Low workbenches of various styles are used by a huge range of specific crafts within woodworking (as well as an equally large number of crafts outside of woodworking). I hope to have sparked some ideas that will be useful in your own work. Even if you continue using a Western bench, I hope you got a hint just what can be achieved with a couple of stops and your body…

While this way of working initially may appear quite simple, this simplicity belies the huge degree of nuance required to get the most out of it… from construction details to actual use. Often it’s not what the bench brings to you, but what you can bring to the Atedai, that determines the benefit it can provide.

You will also have seen that the benches themselves, as well as the methods of using them, are as unique as the craftsman employing them, so if something works for you, and is safe, crack on. There is no ‘one way’ to work with an Atedai, and I would love to see you at work with one of your own.

The best way to get a real sense of these benches in use is to view a range of craftspeople, including some of Japan’s “Living National Treasures,” actually using them, and so I wanted to leave a list of links for you to ‘steal’ some ideas of your own.

Previous Posts in This Series

The Japanese Floor Workbench (Atedai 当て台) by Dominic Campbell – Part 1

The Japanese Gennou & Handle Part 8 – Head Style & Weight

This image has an empty alt attribute; its file name is dsc_0048.jpg — A comparison of two styles of hand-forged gennou heads. Top: A Yamakichi gennou head by Hiroki. Bottom: A classical ryouguchi head by Kosaburo with the antique “swollen eye.” Both handles are made from American Osage Orange, an excellent wood for hammer handles. The top handle still exhibits the neon yellow color typical of OO, while the bottom handle has been exposed to sunlight for a few weeks and turned a nice but unusual brown color.

Better a bald head than no head at all.
Seamus MacManus

In the previous post in this series about Japanese hammers we examined a feature found in all modern hammer heads: the essential, unblinking, unseeing eye. In this post we will touch on the style of heads recommend for using with Japanese chisels. We discussed this subject in this post as well.

Gennou Head Shapes

The most common head shapes commonly available in Japan nowadays are: ryoguchi, daruma, funate, yamakichi and various hybrids thereof.

Ryouguchi

Ryouguch is the most common style of head, at least in Eastern Japan. It has two faces: A flat one for striking chisels and nails, and a slightly domed opposing face for kigoroshi and setting nails below the surface of boards.

While a simple design, this style of head has a relatively high moment of inertia, making it is more stable than other styles and therefore less likely to twist out of alignment during the swing, or twitch upon impact, a positive thing if you are a card-carrying member of NBA (Nail Benders Anonymous). (ツ)

Face designs in this style vary widely including round, oval, square, rectangular (usually with corners removed for a more octagonal shape) true octagonal, and the “Ichimonji” style with roundish sides and a flat top and bottom. We prefer the rectangular shape with cut corners best, but one style is no better than another. We don’t recommend, however, faces with 90 degree corners as the corners are counter-productive during kigoroshi operations and are structurally weaker.

If you are worried about pulling nails, we encourage you to use a nail bar to reduce the number of broken hammer handles wandering the world sad and lonely as a cloud.

A 200monme/ 750gram/ 26oz Modern-style ryouguchi gennou by Kosaburo. Notice the symmetrical shape, slightly flared ends, and the polished “hachimaki” band near each striking face.

A 200monme/ 750gram/ 26oz Modern-style ryouguchi gennou by Hiroki. Compared to Kosaburo’s products, Hiroki’s standard ryouguchi gennou heads tend to have straighter lines, with less flare and no hachimaki. Notice also the different black-oxide skin born in the forge.

The Daruma

The enlightened Bodhisattva Dharma meditating like a house afire

The Daruma (pronounced dah/rhu/mah) gennou head takes its name from a famous Buddhist priest of oval stature who lost both arms and legs through excessive meditation, a blessed state doubtless achieved by many of our enlightened Beloved Customers (spiritual enlightenment that is, not quadriplegia). This gennou head is a stubbier version of the ryouguchi gennou, and always has a round face.

It’s more popular outside of Japan than domestically, for reasons your most humble servant fails to understand. From a physics viewpoint, at a given weight and because of its lower moment of inertia, it is less stable than other styles of gennou, but because it has a bigger face, and is intended to be used at constantly differing angles such that stability is less critical, this style is preferred by carvers. Joiners like it too for cutting repetitive mortise and tenon joints, but it is not favored by most other trades and may invite remarks at jobsites from other workers about the owner being unable to find his derriere with a mirror on a stick and a GPS. That said, your humble servant frequently uses daruma heads for cutting precise mortise joints. Now wait a minute…. where did I set down that darn GPS widget…?

An 80monme/ 300gm/ 11oz daruma head with an rock maple handle.

An 80monme/ 300gm/ 11oz daruma head. Notice the symmetrical shape, round face, precisely-formed eye, and black-oxide forge skin typical of Hiroki’s excellent daruma heads

The Funate

The tail of a funate gennou. This point can be sharpened for creating pilot holes for nails when shipbuilding, or left as a rectangle of starting and setting nails. The face is slightly domed, but still flat enough for striking chisels. A good multi-purpose head that favors nails more than chisels.

The funate gennou is closer in appearance to Western hammers with a skinnier neck behind the striking face, but without the split-tail “piano chisel” a foreman from my misspent youth named Jack Frost called the claw on his 28oz waffle-face framing hammer. It is more commonly seen in the Western Japan than Eastern Japan where I learned Japanese woodworking.

This gennou is useful for finish work involving nails and for tapping-out plane blades, but less useful for wacking chisels.

The Yamakichi

Yamakichi was the name of a gennou blacksmith working in Fukuoka on Kyushu Island that originated this style of head and gave it his name. Kosaburo introduced this style to Tokyo in response to customer demand and with Yamakichi’s permission, we are told, improving the design somewhat.

This style is a heavy-duty stubbier version of the funate with a slightly domed face and a kinda sorta pointy tail, perhaps better suited to driving/setting nails than the ryouguchi head, but certainly better for striking chisels than the funate style.

Better with nails than the ryouguchi style, this head makes an excellent all-round hammer for working in the field, and can even handle tapping-out and kigoroshi tasks.

The design has a unique and interesting appearance which reminds this humble scribbler of a 1956 Ford F100 truck in that, while neither sleek nor smooth, it has a sculptural quality not seen in the other styles that “grows on you.” It feels good in the hand.

There are other in-between head shapes, but these are the four basic styles generally available for woodworking today.

Another view of the Yamakichi gennou pictured at the top of this article after the color has mellowed through exposure to sunlight. This is 300monme/375gram/ 11oz head by Hiroki has an American Osage Orange handle. (The decorative twine was added at the tool’s request. It has a thing for the color red).

Weight

The subject of gennou head weight was examined at some length in a previous post.

Regardless of the type of gennou head you select, weight is a critical factor that will depend on what you plan to hit, your height above the thing you are hitting, how hard you need to hit it, and how precisely you need to hit it. Your own practical experience is the best basis for selecting the genno weight for a particular job, but some guidelines can be suggested.

To begin, the traditional measure used for gennou in Japan is the “monme,” with 100 monme equaling 375 grams or 13.2 ounces (1 ounce = 28.35 grams).

The standard middle-of-the-road weight for gennou used by carpenters in Japan ranges from around 100monme (375grams/ 13.2 ounces) to 120monme (16oz). The most common hammer used for finish carpentry in the United States weighs 16oz. So if you are going to buy your first gennou, and you intend to use it for general finish carpentry or furniture making, a 100 or 120 monme head is a good place to start.

For finer work, an 50-80 monme (7~11 oz) hammer head is a good choice. If you intend to make furniture or joinery, one in this weight range is a must-have.

For cutting deep mortises in heavy timbers with large chisels, as in timber framing or boat work, a 200monme (26oz) hammer is frequently used, but 250 (33oz) and even 300monme (40oz) heads are available. I own and use them when necessary. Some factors to consider when selecting a heavy gennou are that with greater weight comes greater impact force, and greater penetration, but heavier gennou are more tiring to swing and harder to control precisely.

Other factors to consider are the weight of chisels to be used and the width of their blades, since a heavier chisel with a wider blade requires more force to cut to a given depth. Only experience can tell Gentle Reader what weight will work best in a given situation. Just be aware that, unlike athletic socks and gubmint health care, there is no such thing as one-size-fits-all.

Conclusion

We hope this article has answered some of Gentle Reader’s questions on the subject of selecting a gennou head. If you have additional questions or need clarification, please use the “Leave a Reply” form below.

In the next article in our ongoing quest for spiritual enlightenment and metaphysical stability we will discuss the differences between mass-produced and hand-forged gennou heads. We will also consider the necessary attributes of woods suitable for making handles along with more design details in future posts, I promise. Until then, I have the honor to remain,

YMHOS

Japanese Chisel Setup: Additional Notes

A properly setup and hard-used set of excellent mukomachi mortise chisels by Kiyotada. Guess which ones have seen the hardest use over the years and benefited most from proper setup. The blades and handles are all shorter than when new, but without proper setup it is unlikely some of these tools, all of which are at least 30 years old, would still have their original handles, which they do.

Honesty and transparency make you vulnerable. Be honest and transparent anyway.
Mother Teresa

Introduction

Since your most humble and obedient servant wrote the tutorial (located here) describing the advanced procedures we recommend for setting up Japanese chisels ten years or so ago, I have frequently received questions from Beloved Customers about the fact that the chisel setup procedures described therein differ in important ways from those taught by most retailers of Japanese tools in the USA and Europe, as well as those expounded in videos on NoobTube, or posted on the woodworking internet forums.

In response to these questions, I recently added a few paragraphs at the end of the tutorial in question which I am including in this post to dispel confusion among those that have not had the opportunity to read the article.

The Question

The most common question is: “Why does your description of how to setup Japanese chisels vary so much from those given in online videos and the woodworking forums?”

A knee-jerk response to this question might be that the questioner should take a big, heaping spoonful of that online advice, then hold their nose and swallow it down, yes, all the way down, …. keep swallowing now, then judge for themselves after 5 years or so if it is sugar or BS. As the saying goes: “the proof is in the pudding,” or was it “laughter is the best medicine?” We forget. In any case, while such a hasty reply would be entertaining, it would also be crude and unrefined, and since your most humble and obedient servant is nothing if not always elegant, I will instead try to provide a more palatable explanation.

The Long Answer

Yes, Virginia, we have seen the various online videos about setting-up Japanese chisels. The creators of most of them are simply parroting instructions that some long-gone employee of a Japanese wholesaler, someone who had never used a chisel professionally, heard from another guy working at a chisel factory assembling thousands of chisels everyday as quickly as possible from cheap parts, some of which may have been imported from China.

About now, some Gentle Reader may be saying to themselves: “Wait just one frickin minute there! What do you mean, “made in China!?” Please, take a deep breath, smell the napalm, and realize that many of the components assembled into products in advanced countries are actually made in China at low cost. Poor quality is the natural consequence of procurement policies aiming to maximize profits above all else. The components used in C&S Tools’s chisels, however, are all made in Japan of quality materials and to reasonable tolerances.

Here’s the problem: Imagine a chisel handle and/or crown manufactured to such careless tolerances that one must beat the heck out of the handle with a hammer (kigoroshi) to crush and break the wood cells to reduce the handle’s diameter enough so the poorly-matched crown will fit. With this still percolating in your head ask yourself two questions: (1) What sort of attention is being paid to quality control that these two simple parts aren’t manufactured to better tolerances? And (2), will crushing the hardwood handle’s cells improve or harm its durability and/or longevity?

Or imagine, if you possibly can (difficult, we know), a handle and its crown or ferrule so poorly matched that one must swell the wood with water to get the crown or ferrule to stay attached long enough to ship the chisel overseas. Is your mind boggled yet?

Do you suppose poor tolerances or ham-handed setup techniques make for a better chisel, one that will provide good long-term service in the real world? Sadly, this is the grade of chisel with which the PooTube “Creators” and the so-called “experts” on the orc-infested forums have hands-on experience.

The manufacturers of these hardware store-grade tools provide zero warranties. Their products disappear into anonymous overseas markets where consumers are accustomed to being deceived as a matter of course, and the quality of most of their competitor’s products in the local markets, essentially sharpened Chinese-made screwdrivers, are of even poorer quality, so there is no backlash, only profits.

If any of this sounds to you like proper quality control or good value for the consumer, then there’s some swamp land located next to an abandoned chrome plating plant in North Korea, shovel-ready for resort development, that’s for sale at an amazingly low price. We read about it on an internet forum, so it must be true. All you have to do is send US$3,000 in small bills via FedEx to Prince Musa Adebayo at P.O. Box 4, Wassamatayu, Abuja, Nigeria. It’s a limited time-offer, so you’d better hurry. ( ͡° ͜ʖ ͡°)

Most of our Beloved Customers are not new to Japanese tools. They have bought the sizzle before, found it rancid, and come to us for honest handmade tools that meet the rigorous demands of advanced Japanese professional woodworkers.

The Short Answer

Let’s wrap this up by concisely answering the original question.

First, the setup techniques we recommend are different because the tools our Beloved Customers need to setup are different from those to which the “Creators” on SpewTube and the trolls on the internet forums are accustomed. They are made by true craftsmen, not unskilled factory workers using mass-produced components, much less mass-produced Chinese components. Our craftsmen are Japanese gentlemen living and working in Japan using crowns, ferrules, and handles made by them to reasonable tolerances, and the highest-quality hand-forged blades, also made by real Japanese blacksmiths working in their own smithies. Kigoroshi and water soaks are not necessary to setup these chisels, and will not improve them.

Second, because our Beloved Customers selected C&S Tools, we assume they are more advanced than the easily-deceived amateurs that typically buy hardware store-grade mass-produced chisels, and therefore actually want to do initial setup in accordance with the highest standards, not the lowest. It’s their choice, of course, but it would be grossly irresponsible of us to advocate lesser techniques like those of the GooberLube posers or the slimy denizens of the troll pits in the internet forums.

And third, unlike the wholesalers and distributors that peddle hardware store-grade tools overseas at inflated prices, we take our warranty seriously, and therefore actually care about the performance and longevity of the tools we sell. Accordingly, we need our Beloved Customers to set them up properly using the advanced techniques in our tutorial because we have a reputation to protect and a direct financial interest in customer satisfaction.

Five Potential Solutions

We hope the foregoing explanation clears up the original question. In addition, the following list describes five potential solutions to the other problems we touched on above. Sorry, but you’re on your own in the case of Prince Musa:

Purchase only high-quality tools made to reasonable tolerances from quality materials by genuine professional craftsmen and blacksmiths that have long-term relationships and reputations that might be damaged by shoddy quality, not factories;
Buy chisels and other edged handtools only from retailers (like C&S Tools) that not only offer but actually honor a full international warranty on materials and workmanship, one that doesn’t require you to expend additional funds to benefit from. Good luck finding anyone else;
Beware the often well-intentioned posers on Yoogle’s GooTube (or is it Toogle’s YouGube? We forget) who specialize in spinning an ounce of BS into 7 minutes of visual entertainment, all without any responsibility for the accuracy, completeness or honesty of their representations;
Beware the chittering of the pustulous trolls and grunts of the execrable orcs scuttling about in the fetid darkness of the internet forums;
And last but not least, always remember the most reliable litmus test for veracity: Money Talks and BS Walks (see point 2 listed above).

Or, you can always try the spoon test described above: Bitter lessons teach surest. (ツ)

YMHOS

A properly setup and hard-used 10-piece set of oiirenomi chisels by Kiyotada. Guess which ones have seen the most use? All the handles and most of the blades are significantly shorter than when new, but the handles are entirely undamaged, proof that proper setup pays dividends. I need to tap-out some of the blades again.

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.

Toolchests Part 7 – Key Performance Criteria Solutions 2: Sealing, Insulation, Security, Portability & Tiedown

Bernini’s David, completed in 1624. I have seen all three of the famous David sculptures in-person, but this is my favorite because David is not depicted as a static, obviously posed, formulaic study-in-marble or bronze of the human form as he is by the other masters. Instead, Bernini used his chisel to tell a dynamic story of a young man staring intently into his huge, deadly enemy’s eyes as he winds up to deliver a sling stone to his fuzzy forehead, a single, unlikely rock that changed world history forever. Although Bernini portrayed the face of a shepherd boy risking all in front of two opposing armies, this determined visage could just as well be that of a surgeon, a baseball pitcher, or a woodworker, of course.

Three things are needed for success in painting and sculpture: to see beauty when young and accustom oneself to it, to work hard, and to obtain good advice.
Gian Lorenzo Bernini

In the previous post in this series about toolchests we examined solutions to two of the Key Performance Criteria your most humble and obedient servant established when planning this toolchest, namely durability and longevity. In this post we will examine the solutions to three more performance criteria: Sealing, Insulation, and Security. It may be long, but I hope Gentle Reader will at least find it diverting.

Sealing & Insulation

Sealing the toolchest tightly and insulating it are important factors to consider when planning a toolchest, as mentioned in previous posts in this series, because a leaky chest can allow cold air, dust, excess humidity, and insects access to the tools stored inside it, potentially soiling, corroding, and damaging them. There are several details one can include in a toolchest design to minimize this problem. Some of the measures I employed are explained below.

The Lid

The criticality of a toolchest’s lid in sealing and insulating it over many years cannot be overstated. Unfortunately, many historical examples eventually failed miserably either through poor design or poor execution. Your humble servant was determined to avoid those failures.

As I mentioned in previous posts, chests in museum exhibits and books all look great, many having been at least partially restored, but if Gentle Readers want to get a sense of how chests fail, they should also inspect the busted examples collecting dust in antique stores and restoration shops.

While my investigation was not exhaustive, the first common failure inspecting antique chests revealed was a poor seal at the lid. This is almost universal. In the chests I examined it frequently stemmed from a poorly-fitting lid, one that probably fit nice and tight when new but warped over time.

In other cases, the lid had cracked and split like the seaman’s chest in the photo at the end of Part 2 of this series.

Another common problem was due to what could only be an intentional gap on the hinge side of the lid. And then there were the gaps caused by thin, narrow and weak iron hinges secured by short wood screws bending, wearing and/or loosening. So how to avoid these problems?

Let’s consider wood first. A policy that has served me well over the years is to always assume that a solid board of more than a few inches in length will eventually warp if left to its own devices. Of course, in the real world this is not always the case, but I’m a belt & suspenders & safety harness kinda guy. Besides, remember the 200 year useful life-cycle objective.

I also assume that a board more than a few inches wide will eventually split, or cause damage to another board in the assembly, if overly constrained from responding to both normal seasonal changes in humidity and the unnaturally dry conditions created by air conditioning systems inside modern buildings. Am I overly cautious? Perhaps more so than the optimistic captain Edward Smith of the RMS Titanic was on a cold night in April 1912.

The historical record represented in the museums and antique stores I visited support these assumptions in the long-term, especially when one considers the effects of AC and central heating systems lacking expensive humidity controls. Therefore I designed and constructed the lid so it included no constrained boards more than 2-13/16″ inches in width. In addition I also reinforced the lid from warping as a unit to prevent it from self-destructing during the planned 200 year useful lifespan. Not that hard to achieve with a little thought and a few sharp saws, chisels and planes.

Strength, Durability, and Rigidity of the Lid

As will be revealed in Part 8 of this series, a large number of tools are mounted inside the lid, the cumulative weight of which would cause a simpler, lighter lid to flex, twist and fail rather quickly, I fear. To provide the strength, durability and resistance to torsion needed, I went with a more complicated design.

Instead of having a simple flat board lid or one using F&P construction, this one is comprised of two sub-assemblies: A horizontal top F&P panel joined to the lid’s vertical side assembly.

Frame and panel (F&P) construction is a technique which allows the craftsman to build wide, stable surfaces using a joined framework of narrower pieces of wood with free-floating panels set in between. The framing pieces are narrow enough to accommodate cross-grain construction at the joints safely. The larger inset panels are too wide to permit cross-grain construction without their eventually failing, so they are not glued to the frame members, but are free-floating in grooves so they can expand/contract with humidity changes without cracking, splitting or breaking the frame. Gentle Readers who have never done F&P work before should learn how, for it is a skill every self-respecting maker of solid-wood casework or joinery must have.

Side view of the toolchest. Once again, please notice the frame & panel construction of the top and depth of the lid, a detail which provides great strength and stability to the normally failure-prone lid. A hardened steel lifting/tie-down ring through-bolted to the sidewall is also visible, as is the end view of the torsion-box base with urethane wheels which makes it possible to move the toolchest over level surfaces and up loading ramps when full of tools without damaging floor finishes.

The top panel’s frame consists of 6 pieces of wood 30mm (1-3/16″) thick by 70mm (2-13/16″) wide. Four perimeter pieces are joined at the corners using pinned (wooden dowels) dovetailed bridle joints to form a rectangular frame 1,015mm (39-15/16″) x 595mm (23-7/16″). Two pieces of the frame divide the long dimension of this rectangle into 3 equal-sized spaces filled with 21mm (13/16″) thick free-floating raised panels contained by tongue and groove joints. Both tongues and grooves are coated with Briwax (beesewax and naptha) to prevent glue squeeze-out and paint from gluing the panels into their grooves, something that happens frequently and almost always causes the panels to crack and even split.

I just hope that future generations are wise enough to not refinish the chest by glooping paint on these joints effectively gluing the panels in-place eventually destroying the lid. Much excellent antique woodwork has been destroyed by careless painting.

Given the thickness of the frame, the sturdiness of the corner joints, and the quality of the wood, the lid is an extremely stable construction all by itself, one that has not warped or cracked in 25+ years. Good enough, perhaps. But wait, were are my suspenders?!

This flat top panel is attached by glue and wooden pins to a four-piece vertical perimeter framework that extends downwards an additional 130mm (5-1/8″) making the total external depth of the lid 160mm (6-5/16″). The four vertical boards of the side assembly are also 30mm (1-3/16″) thick, joined at each of their four corners by 7 pinned through-dovetails. Even if the glue fails someday, the pins will keep the dovetails locked in-place. This construction makes the lid assembly extremely rigid and resistant to wracking preventing the top and sides from warping. This lid assembly has never cracked, warped, stuck, bound or even squeaked. Not once.

Besides providing stability and a gap and crack-free seal, this construction creates the space I required to house many heavy tools inside the lid as well as the structural strength to handle this heavy load without noticeably flexing or twisting. This is directly related to Performance Criteria No. 4: Accessibility.

But this is a lot of weight to deal with so I was concerned that, like many antique chests, the forces required to open and close the lid would eventually cause the lid to fail, or at least make the top panel to separate from the side assembly over decades of use, ruining the lid’s functionality.

Opening the Lid

The solution I selected was to design the lid so that the only way to open it is to use the wooden handle secured to the front board of the side assembly by tenons, glue and heavy screws from the inside. In this way, the forces acting on the lid will always keep the top panel and side assembly together instead of tending to separate them.

To ensure using the handle is the only way to open the lid, I intentionally did not design a projecting lip at the perimeter of the top panel. This was a difficult decision because the addition of such a lip would appear more classically graceful in the Western tradition. But the temptation to use the lip to open the lid would be overpowering to future generations, eventually weakening and even destroying the lid. This too is something I observed in antique chests.

While these design details made the chest extremely strong and durable, they do give the chest a bob-tail appearance, such that it looks more like a box than a typical Western chest. Being a belt, suspenders and full safety harness kind guy I believe the improved performance more than justifies the compromise in aesthetics.

Iron Mongery

A wide, bold surface like this lid with exposed joints just begs for the addition of engraved metal plates and hand-forged straps of the sort easily obtainable in Japan. I freely admit that decorative hardware would really look cool, but I managed to avoid the temptation because history shows that, if firmly affixed to the wood, metal plates and straps tend to constrain the wood’s natural expansion and contraction often eventually opening joints and cracking the wood totally defeating the purpose of the elegant frame and panel construction. None of that nonsense for me, you wascally wabbit.

Front and top view sketches of the toolchest with minimal dimensions. All the drawings will be available for free download in a future post.

The Seal Between Lid and Case

Chests made in the tradition of Western countries often have an interlocking lip between lid and base which more or less seals three sides, but which leaves a gap at the hinge side where dust, humidity, cold air, fungi, insects and pixies can enter. That’s nonsense. But what are the realistic options?

One well-published toolchest intelligently overcomes this sealing problem by using hinges supported on corbels attached to the exterior back wall of the chest. I think this is a clever solution, and one I long considered, but ultimately rejected because it increases the toolchest’s overall width by the corbel dimension without increasing internal storage space.

I also considered rubber gaskets, and even magnetic refrigerator gaskets. Either would have sealed well at least until the unavoidable day of reckoning when the rubber and plastic oxidized, cracked and crumbled. They won’t last 200 years anymore than Cher’s beauty will. Oops, too late.

The solution I eventually settled on was a detail common to Japanese casework, namely a vertical lip applied to the inside of the lid where it meets the lower case. While not quite airtight, this lip does ensure the lid and case are precisely aligned when closed, that there is no gap at the hinge side, and that very little cold air, dust, fungi, bugs, or even anorexic pixies can infiltrate the toolchest once closed. I used a tough, fibrous, exotic hardwood for this lip that has held up well. The seal is so good that, even with 25 pounds of tools mounted inside the lid, I can drop the lid from full-open and the air-pressure created by this tight seal will make the lid close slowly without a sound. I have not had to replace it in 25+ years, but it would be easy to do if necessary.

This simple detail, combined with the natural thermal properties of the 30mm thick wooden sidewalls and lid, satisfied the criteria for insulation too.

Hinges

We discussed a few methods involving wood to prevent drafty lids above. Next let’s examine metal hinges.

Another failing of antique chests common to all the traditions I was able to investigate was inadequate and/or poor-quality hinges. When hinges are lose and sloppy when new, or become loose and sloppy over time due to wear and/or corrosion, or when the tiny, often poor-quality nails, staples or screws used to attach most hinges loosen and become “idiots,” as they say in Japan, the lid won’t align with the case and/or a gap develops between lid and case. Secondary damage results. Dirt, air, bugs and pugilistic pixies penetrate. It’s the beginning of the end.

This image has an empty alt attribute; its file name is Pandora_by_Arthur_Rackham.jpg — Another look at that horrendous pixie infestation in a toolchest with a leaky lid located in a clothing-optional workshop. Bad hinges, no doubt. How embarrassing!

Traditional blacksmith-forged iron or steel hinges with decorative engraving or hammer marks are extremely attractive, but they just don’t meet my performance criteria. To begin with, iron/steel always rusts, with the corroded steel expanding in volume, becoming abrasive, and destroying tolerances, a nasty cycle. Handmade hinges look cool, but tolerances are poor. And most importantly, traditional hinge pins are short and small in diameter with tiny bearing surfaces that wear quickly, and since their ends are peened, they cannot be removed easily. That would never do.

Instead of installing pretty traditional hinges or the cheap hardware-store hinges most people use for chests, I chose to use five solid-brass commercial door hinges with removable steel pins, made possible by the 30mm thickness of the case walls. I give them a dab of oil every couple of years. There is a reason modern door butt hinges can endure a lot of wear and abuse, and it has nothing to do with historical accuracy, I assure you.

I inset both leaves of these hinges and fastened them using 2″ long grade 18-8 stainless steel screws (made in the USA not China) after dripping glue into the holes. They have not loosened or even developed a squeak in 25+ years.

The long strap hinges used on American and British chests may look sexy, but they often cause the lid to crack and split. Think about it.

Security

More often than not, quality chests have historically had locks of one sort or another installed. If you, Gentle Reader, decide your toolchest needs a lock, you should develop a security strategy early in the design process. Here’s mine.

As part of my day job planning restricted-access facilities for Clients that have a lot to lose if their corporate secrets are stolen, I’ve talked with many building security experts. I’m not suggesting you need 10-lb locks with biometrics, multiple layers of 1/2″ hardened plate steel doors, contact switches, keypads, video cameras backed-up live in Colorado, or armed guards. But I can share with you something I have learned applicable to cabinetry.

A lock on a wooden cabinet or chest won’t dissuade a determined thief with a crowbar for even a minute, but it may help keep an honest man honest.

But thieves are not all we need to worry about.

Ever have one of your adoring children or your loving spouse (yes, the one that thinks you have too many tools already and should buy new kitchen counters instead) borrow a tool, or even worse, lend it to a friend or neighbor without telling you? How often did that tool find its way back to its proper place in your toolbox or workshop?

How often has one of your precious, carefully-sharpened chisels ended up being used as a combined paint can opener and stirring stick only to spend the following months or years smeared with paint, humiliated, alone, forgotten, sadly weeping behind old paint cans in your neighbor’s garage? Besides the indignity of paint spots (chisels are often vain, you know), imagine the emotional trauma the poor thing suffered. Not to be borne….

To help preclude this trauma, Gentle Reader has three choices when it comes to casework locks. The first is to use standard locking hardware that requires a modern keyed lock with a tumbler or a combination lock. These work pretty well, but most look ugly in handmade casework. Appearance aside, the most serious problem with such locks is that, given time and privacy, and lacking lock-picking skills, a determined thief will simply break wooden casework with a crowbar. We see this sort of damage in modern cabinets frequently. It’s expensive to repair.

The second choice is to use heavy bars, locks and chains. I use this technique when I ship my toolchest by first padding the chest with plywood and blankets and then running a 10mm hardened-steel chain (chain-hoist chain) around the chest through the hardened-steel lifting eyes on both ends crossing underneath and on top of the case. This I secure with a heavy, high-security padlock underneath the rolling base. Hand-powered bolt cutters won’t cut the locks or chain, but a largish hydraulic bolt cutter could. Likewise, an angle grinder could get through given some time, noise and sparks. This is a lot of trouble both for me and the thief, but it will absolutely stop a pilferer with a crowbar. 30mm thick sides and lid, remember. But it is not at all practical for routine access to the tools inside.

The third method is to install a lock that is convenient to use but easily defeated so a determined thief won’t destroy the chest in the process of bypassing it. A strange approach, I know, but it is logical and practical. The locking system I selected is a simple, old-fashioned brass half-mortise chest lock. You could pick it with a hairpin if you know how, or pop it open with a claw hammer. It’s quick and easy to lock and unlock, and it deters rugrats, wives, casual pilferers and even pernicious pixies, all while looking classic and unobtrusive. If a determined thief has the opportunity, he can easily break the lock and get in. The upsides are that he can do it without destroying the chest, and you will know he did it. Not ideal, but nothing ever is.

Portability

The portability criteria I established during the planning phase required the toolchest be light enough in weight to be carried up stairs by two men when empty. It had to also be easily moved over flat surfaces by one man with a full complement of tools inside.

Gentle Readers may recall the following image of a Japanese kuruma dansu from Part 2 in this series. This tradition served as inspiration for my design.

In Japan this type of chest is called a “kuruma dansu 車箪笥,” which translates to “wheeled chest.”

You may wonder why anyone would need wheels on a piece of casework intended for interior use. The reason is simple practicality: Japan has a long history of urban fires that destroyed entire cities on a regular basis, but the addition of wheels to casework made it possible to quickly roll them out before the house burnt down, thereby saving valuables. Try doing that with a wall cabinet! Or try doing it over unpaved streets with tiny fragile casters screwed to the base of a loaded chest.

Wooden wheels are cool and mecha retro, but I rejected them for two reasons. First, they have solid axles, and if rolled around much both the wheels and the floor will be damaged, a lot, especially once grit and small stones become embedded in the wood. Not practical.

The second reason is more complicated. To begin with I wanted to be able to remove the wheels at times to comply with the maximum height criteria I had established in order to move the chest up narrow Asian stairs. Even with the current design, I need to remove the lid to get it up some stairs, including the house I currently live in.

The wheels in a kuruma dansu not only add a lot of fixed additional height, but that height is volume I would prefer to have inside the chest for tool storage instead of being occupied by an integral undercarriage, wheels and axles. But by using a detachable torsion box base with modern extra-heavy-duty lockable industrial casters with urethane tires, ball-bearings, and crazy pivots (free to rotate around a vertical axis), I was able to raise the chest further above the floor to improve access, satisfy the maximum height and portability criteria, and secure more interior space. If the casters go bad, I can replace them easily without impacting the chest in any way, unlike some examples where the casters are screwed directly to the bottom of the chest.

Besides, there have been a few years when the toolchest spent time in state (in full view) in our living rooms, and while my wife is Japanese, she simply doesn’t like the appearance of kuruma dansu. Go figure. During those periods, I simply removed the wheeled torsion box and rested the chest directly on the floor. My wife placed a colorful cloth noren over the chest with a flower vase on top. Some of her lady friends from church who visit occasionally liked it enough to ask if I would make chests for them.

Tie-down & Lifting

The performance criteria for tie-down and lifting were as follows: “Can be secured to the walls or floor of a shipping container or moving truck, and lifted by crane quickly and easily and without employing complicated rigging or straps touching the wooden surfaces.”

As seen in the picture above, a hardened steel ring is through-bolted to each endwall of the toolchest. These are not reproductions or homemade rings, but industrial load-rated hardware made from hardened steel that serves three purposes. First, they make it easy to secure the toolchest to the side or floor of a container or truck. This capability is very important in the case of a toolchest that must make international moves frequently. If you think it would be easier to just have the movers throw blankets over the chest and strap it down, you’re absolutely right. The problem is that the likelihood of the conscientious, patient, gentle, sober professionals that load conex boxes and trucks properly positioning the toolchest so it won’t shift, and then tightening the straps or ropes (if they even bother to use straps or ropes) so they don’t loosen, or scratch and abrade the toolchest, are slim and none, and Murphy always goes out drinking with Slim on moving day. I’ve seen them share a doobie afterwards.

The second purpose of these rings is to make it easy for two men to carry the (empty) chest by looping straps through each ring and over a 2×4 passed over the chest and placed on each man’s shoulder. This too is a traditional Japanese method of transporting heavy boxes, and is directly related to the “Portability” criteria discussed above.

And third, if I need to chain the chest closed to prevent pilfering, as I do when it is stored in a warehouse, I can pass a hardened chain through the rings, over the top and secure it with a padlock under the base without fear of the chain being slipped off, as described above under “Security.”

Sorry this article was so long. Perhaps these scribbles will suggest some solutions to Gentle Reader’s tool storage systems.

In the next post in our tale of supernatural beings and nekid workers in workshops we will take another look at hinges and examine the tools mounted inside the lid.

YMHOS

Keep your frikin sticky fingers out of my toolchest!

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 screws in my hinges all dance the reverse macarena.

The Japanese Gennou & Handle Part 7 – The Unblinking Eye

Tempo is all, perfection unattainable,
As at the top of the swing… …there’s a hesitation, a little nod to the gods, that he is fallible. That perfection is unattainable.
“The Golf Swing” by Roy McAvoy

The Japanese gennou is outwardly the simplest of hammers comprised of just a differentially-hardened steel head attached to a wooden handle without wedges, pins, epoxy or rubber. But as simple as it is, there are several factors that drive this tool’s performance. One critical factor is its “eye.”

The Unblinking Eye

Since ancient times, hammer handles have ended in a “tenon” designed to fit inside a rectangular through-mortise hole in the hammer’s head called the “eye,” in English, and “hitsu” in Japanese. In both Western hammers and the majority of Japanese hammers the interior walls of the eye are angled so that a wedge driven into the end of the handle will splay the tenon keeping it from slipping out of the eye. This connection works as well as can be expected, if the eye is deep and tolerances are acceptable, but Japanese gennou heads are compact and their eyes are not deep, so a better solution is called for.

The downside to securing the head with a wedged tenon is that the wedge will frequently cause the handle to split weakening it considerably. Also, a wedged connection seldom has uniform contact and pressure inside the eye and may therefore loosen as the wood wears from impact forces. In addition, uneven pressure between tenon and eye may induce unpleasant vibrations in the handle, a phenomenon you have not doubt experienced without realizing it, like an itch on the back of the neck felt long after the pesky mosquito’s smash and grab.

A tight, high-friction, uniform-pressure fit between the eye’s walls and the tenon keeps the quality Japanese gennou head in place and working efficiently. Straight, parallel, square, clean walls are therefore critical.

Inexpensive mass-produced gennou and hammers typically have eyes with poor tolerances hidden by the handle tenon and sometimes concealed under resin caps. The heads and handles of such hammers and gennou seldom remain securely attached if used heavily long-term. Experienced Japanese professionals, therefore, have traditionally preferred to buy just the head without a handle so they can inspect the quality of the eye before laying down any money, and then make the handle themselves. This is consistent with the frugal craftsman ideology once common throughout the civilized world wherein the craftsman would make as many of his own tools as possible, often in imitation of his master’s tools and using metal components forged by the local blacksmith, all to be completed by the conclusion of his apprenticeship and graduation to “journeyman.”

This explains the demand in Japan for high-quality relatively expensive heads such as those hand-forged by Kosaburo or Hiroki. Not only are they properly shaped and consistently heat treated, but they have precisely dimensioned eyes that will not only hold onto the tenon a long time and reduce unwanted vibrations, but will save the owner a ton of effort both truing the eye and replacing failed handles later. And since the gennou is a lifetime, heirloom tool, the extra cost of such a head is not wasted.

Four hand-forged gennou heads: L~R 375gm Kosaburo Classic; 100gm Hiroki Modern; 338gm Hiroki; 300gm Hiroki; 25gm Hiroki. All differentially hardened. All made entirely by only power-hammer, forge, and grinder by hand. Dies, presses, mills, CNC equipment, EDM equipment were not used to shape these heads or form these eyes.

Mr. Aida studied under Kosaburo. Although their styles are different, most notably the lack of a polished “hachimaki” headband in Hiroki’s products and the very different oxidized forge skin, both blacksmiths made/make precise eyes.

Since so much relies on the connection between the handle’s tenon and unseeing eye, let’s examine it and correct any deficiencies revealed.

Examining the Eye

The first step in inspecting a gennou head is to check the eye because if this is wrong, then the head will not only be difficult to make a handle for, but it will be unstable during the swing and skittish on impact, intolerable failings in a tool we need to use with speed and precision unconsciously.

Just sight down the length of the head’s body with the eye in view. The eye should be of uniform width over its entire length, and the sides parallel, of course. It should also be centered in the body and not skewed. The narrow end surfaces of the eye should also be straight and square to the sides. Mass-produced gennou heads typically fail this examination to some degree, and even some expensive handmade heads will too, sorry to say. Be sure to inspect they eye this way on both sides of the head.

560gm Kosaburo Classic-style gennou head. Old-stock with surface patina. This is how all Japanese gennou were shaped prior to around 1890. The swollen area around the eye was created by the pressure of the mandrel being hammered into the yellow-hot metal to form the eye. This bulge was also once common in European and American hammers.

560gm Kosaburo Classic-style gennou head (slightly rusty).

Next you need to inspect inside the eye. Use a flashlight to check the interior walls are straight, parallel, square, free of twist, and without significant bumps, bulges or gouges. You may need to make a tiny square from wood or metal to perform these checks. There are special machinists squares and depth gauges that are ideal for this purpose. An accurate caliper will prove useful.

Ofttimes the eye’s walls are intentionally sloped inwards from both ends so the center of the eye is narrower than either opening. This geometry is intended to compress the tenon as it is driven through the constriction locking the tenon into the eye. The crushed tenon is then supposed to expand afterwards, essentially relying on kigoroshi to bind the tenon in the eye. This geometry does work, kinda sorta, if a wedge is driven into a sawkerf cut into the tenon. Gennou heads with this style of eye are much easier to produce and are intended for mass-production beaters. Such head/handle combinations may exhibit strange harmonic vibration, which you may or may not be able to detect, and since pressure on the wooden tenon is not uniform, swelling/shrinking of the tenon with seasonal humidity changes will always cause the head to loosen over time.

If a gennou head is secured to the handle with wedges, it may be because the eye is sloppily made, or just because that is what amateurs are accustomed to seeing, but a quality gennou head fitted to a proper handle does not need wedges to secure it no matter what Fat Max says.

Correcting the Eye

As the philosopher and erstwhile golf poet Tin Cup taught the World: “Perfection is Unattainable,” so I don’t encourage anyone to go OCD over the hole in a hammer head, but if you are patient, you can use small files to true the unseeing eye to the best of your patience and ability. This is a tedious job because only small files can be used, and that within a narrow space both difficult to see into and with little room to develop leverage.

Related image — Kevin Costner as Tin Cup testing various apparatus to correct his golf swing which he laments “feels like an unfolding *lawn chair*.” Woodworkers too are susceptible to the allure of commercial mechanical fixes such as honing jigs and sawing jigs despite the solution being in themselves.

Please be careful when filing to avoid making things worse. Remember, flat, parallel walls free of twist with clean sharp corners are the goal. Once you have trued one poor quality eye you will understand the value of a high-quality premium gennou, which has nothing to do with finish or decoration.

If your gennou head has a constricted eye, please file all four walls straight.

Whatever you do, don’t leave the walls curved outwards so that the eye is wider at any point inside than at its openings, because the handle can never be properly fitted to such an eye and will always work loose.

Make a Layout Tenon

Once the eye of your gennou is true, cut and plane a piece of softwood that perfectly slip-fits into and through the eye with 3 or 4 inches protruding out both sides. Draw lines on the stick where it projects from both ends of the eye. We will call this stick the “layout tenon.” Save it to use later in the handle-making process.

In the next post in this series on making a handle for the Japanese gennou hammer we will look at selecting a gennou head.

YMHOS

Comparing Mass-produced Heads to High-quality Hand-forged Heads

Heat Treatment

Precision of the Eye

Precision of the Face

Improved Dynamic Performance

Appearance and Pride of Ownership

Conclusion

Previous Posts in The Japanese Gennou & Handle Series

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Inside the Lid

Other Posts in this Series:

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Introduction

Disclaimer

Sawing

Planing

Chisel Work

Standing & Sitting

Miscellaneous

Conclusion

Previous Posts in This Series

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Gennou Head Shapes

Ryouguchi

The Daruma

The Funate

The Yamakichi

Weight

Conclusion

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Introduction

The Question

The Long Answer

The Short Answer

Five Potential Solutions

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Sealing & Insulation

The Lid

Strength, Durability, and Rigidity of the Lid

Opening the Lid

Iron Mongery

The Seal Between Lid and Case

Hinges

Security

Portability

Tie-down & Lifting

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The Unblinking Eye

Examining the Eye

Correcting the Eye

Make a Layout Tenon

Previous Posts in The Japanese Gennou & Handle Series

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