Sharpening Part 28 – The Minuscule Burr

Do the difficult things while they are easy and do the great things while they are small.

Lao Tzu

A key milestone Beloved Customer should aim for when sharpening a blade is the production of a “burr” at the edge when abrading the bevel (not the ura) using the first rough stone in the series. The formation of the burr indicates that the extreme edge of the bevel side of the blade has probably been abraded enough.

In this post in the Sharpening Japanese Tools Series, we will examine how to raise this burr and why it is important to do so, how to use the burr to test the condition of the cutting edge as you are sharpening, and how to transition from one stone to the next finest stone in the series

Raise a Burr

The steps in creating and then abrading away a burr. The size of the burr in step 2 is grossly exaggerated for clarity. Indeed, unless severe damage to the edge needs to be repaired, you should not normally be able to detect the burr by Mark 1 Eyeball alone.

Japanese plane and chisel blades tend to have harder steel at their cutting edges than Western chisel and planes, and consequently, their steel does not exhibit the plastic deformation necessary to readily produce large burrs, or “wires” as some people call them, when being sharpened. In fact, “burrs” on professional-grade Japanese chisel and plane blades may be difficult to detect.

The key point to remember is that the formation of a burr is only a milestone in the sharpening process, not a goal. A clean, uniform, smooth burr signals the elimination of all major defects, chips, and dents at the cutting edge. Indeed, if we seek an efficient cutting edge, we must remove through abrasion enough metal to also remove the deepest defect in the cutting edge. But regardless of the ductility of the steel, a large, loopy burr or “wire” is not desirable because it will tend to break off prematurely leaving a jagged, ragged edge that will actually set back the sharpening process.

The milestone we need to pass in the sharpening process as soon as possible is the creation of a barely-detectable, tiny and clean burr. My advice is to produce it by abrading only the bevel side of the cutting edge on your roughest stone, although you may not be able to test if it is clean until after a few strokes on the medium-grit stone (1000 grit).

As we discussed in a previous post in this series, the way to keep the size of the burr minimal and the blade’s bevel flat is to focus the pressure of abrasion as close to the extreme cutting edge as possible, but without overbalancing and gouging the stone and dulling the edge. This is the most essential skill in freehand sharpening.

Now that we have a burr, let’s test it.

Testing the Burr

As you are working to produce the burr, you will need to frequently and quickly test its progress, but that can be difficult, if not impossible, to do by eye alone.

To make this process easier and quicker, rub the pad of your thumb or finger over the ura’s edge, away from the cutting edge, thank you very much, when using your rough stones. Your fingerprint ridges will snag on the burr long before you can see it. If the edge is chipped or damaged, the burr will not be consistent but will be interrupted at each defect. There is nothing at all to be gained and much to lose by allowing the burr to become larger than absolutely necessary, so pay attention.

Once you have produced a small burr the full width of the cutting edge, and confirmed its existence with your fingertips, you then need to test it for defects. If you run your fingernail along the burr’s length (the width of the blade), your fingernail will snag on nicks and defects in the burr, something your nerves can sense long before your naked eye can detect them. Keep working the blade’s bevel on the rough stone until the edge and/or burr is consistent across the full width of the blade, and free of nicks, dents and chips.

In the case where you need to remove serious damage to the cutting edge, you may want to use a loupe to ensure the defect has been transferred entirely to the burr and no longer remains in the cutting edge.

In the case of quality Japanese woodworking blades, if you are careful to focus the abrasive effect of the stones on the extreme cutting edge instead of the rear of the bevel, the burr created before moving onto the medium grit stones should be barely detectable or even non-existent. Once again, except in the case of removing large nicks, chips or other severe damage, creating a big burr is not only a waste of time, stones and steel, but if, heaven forfend, the large burr is torn off during sharpening, it will leave behind a tragic amount of damage that must be repaired by once again abrading the edge and raising a new burr. Don’t start chasing that tail.

Best to create just enough of a burr to confirm that damage has been removed and then encourage it to evaporate.

Don’t forget to check the angle of the bevel with your hand-dandy bevel gauge. See the section on Pixie Predation Prevention & Pacification in Part 11 of this series.

After the burr is in good shape, polish the bevel on the medium and then fine stones. The burr will be polished away evaporating without special effort.

Finally, polish the ura side of the blade on the finest stone you intend to use. Feel the burr with your fingerprints and check it with your fingernail. Then polish the bevel on the fine stone. Repeat this front and back polishing process until the burr is polished away entirely.

Assuming the ura is already polished on your finest finishing stone, you shouldn’t need to touch the blade’s ura again on any stone until the final finishing stone.

Transitioning From One Stone to the Next

Recall that the purpose of each stone used after the roughest stone in the series is simply to replace the deeper scratches left by the preceding stone with finer scratches. In fact, there is nothing to be gained and much to lose by moving onto a finer stone before all the scratches from the previous stone have been replaced, so please check that all the scratches from the previous stone have been polished out before moving to the next.

This is not always easy to confirm without magnification, so to make it easier and surer, I suggest you skew the blade’s bevel on all stones but the final finishing stone for the last 3 or 4 strokes creating new diagonal scratch marks on it.

These skewed scratches will be at a different angle than those produced by the next stone, of course, and will be easy to differentiate from the new scratches with the nekid eye. When the next finest stone removes them entirely, you will know you have probably spent enough time on that stone, and can go to the next. But don’t forget to skew the blade again before going to the next stone.

Of course, there is no need to skew the blade on the final finishing stone.

Summary

We have discussed three important sharpening techniques in this article which you must master if you have not already:

  1. Raise a burr by abrading the blade’s bevel on your rough stones using your skillful technique;
  2. Test the burr for size and completeness using your fingertip ridges, and for defects using your fingernails. If the burr is incomplete or has detectable defects, continue to work the blade on the rough stones on the bevel side only until the burr is good.
  3. Skew the blade during the last 3~4 strokes on each stone (except the final finishing stone, of course) to create diagonal scratches. When all those diagonal lines are polished off by the succeeding stone, you will know it is probably OK to move onto the next finest stone in the series.

You now have powerful tools at your disposal that can sense the state of a steel blade as thin as the edge of nothing, and without using your eyes, tools you’ve always had and which didn’t cost you a thing. How’s that for value? (ツ)

Be forewarned, however, that if you use these techniques you may be forced to choose between a glamorous career as an international professional fingernail model or the quiet life of an expert woodworker. What to do, what to do…..

In the next and final post in this series we will use all the aspects of the sharpening process discussed previously to sharpen a blade step-by-step. Be there or be square.

YMHOS

The University of Tokyo’s Yasudo Kodo building hidden behind Autumn Ginko leaves.

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.

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The Challenges of Professional-grade Japanese Chisels

Hammers to Use With Chisels Part 4 – The Chisel Cha-Cha

A Japanese sashimono-shi at work using his atedai workbench and foot clamp.
Stan Laurel

You can lead a horse to water, but a pencil must be led.

Stan Laurel

In previous articles in this series about hammers to use with our chisels, your humble servant discussed the varieties of suitable hammers, the appropriate faces on those hammers, and recommended some weight guidelines. In this article we will examine some important hammer and chisel techniques Beloved Customer should consider to make your chisel work more efficient and your chisels last longer

The Chisel Wiggle

Something to keep in mind about our chisels when beating on them is that their cutting edges are intentionally and carefully hand-forged and heat treated by experienced blacksmiths (none with less than 40 years independent experience) to be especially hard to meet the demands of professional craftsmen for the extra sharpness and cutting longevity only hard, fine-grained steel makes possible. They are not the crude, sharpened Chinese screwdrivers sold by the big corporations that amateurs are accustomed to using nowadays.

To maximize the advantage such excellent steel affords, Beloved Customer must avoid driving the chisel so deeply into the wood when cutting mortises, for example, that the extreme cutting edge binds in the wood forcing the user to forcibly wiggle the chisel forward and back to loosen and extract it from the cut. I call this undignified movement the “chisel wiggle.”

Your humble servant realizes this is contrary to what many woodworking gurus with their soft-as-butta chisels teach, but I unabashedly assert that it is irresponsible behavior in the case of our professional-grade tools because binding the blade in the wood this way creates what I call a “high pressure cut” situation, placing a tremendous amount of clamping force on the thin metal at the extreme cutting edge. Doing the “chisel wiggle” in this situation will damage the cutting edge dulling it quickly. If you doubt this, please dig out your hand-dandy loupe and do a before-after comparison.

In addition, the time lost extracting the wedged-in-place chisel and the resulting interruption in the workflow caused by repositioning one’s hands, and perhaps even setting aside the hammer (egads!) while doing the chisel wiggle, makes it impossible to maintain an efficient cutting rhythm. If you doubt this, we double-dog dare you to do timed comparative tests. The difference in efficiency will become instantly clear.

People accustomed to using Western chisels with their softer, plasticy blades made from high-alloy high-scrap metal content steel with higgledy piggledy crystalline structure are actively taught to use the chisel like a crowbar to lever waste out of cuts. This is another type of “high-pressure cut” that damages the tool’s cutting edge at the microscopic level.

The mass-produced screwdrivers sold as chisels in the West nowadays are tough but relatively soft, can’t be made that sharp to begin with, and they dull significantly during the first few hammer strikes anyway, so most people can’t detect the edge degradation the chisel wiggle and prying produce.

Those who are satisfied with sharpened screwdrivers don’t buy our chisels anyway so I have no advice for those poor benighted souls, only prayers: Namu Amida Butsu. But it is of little matter because they seldom have the sharpening and tool skills required to tell the difference anyway. Horse, meet water; Ah… not thirsty I see.

The Chisel Cha-Cha

Now that we have explained what not to do, let us examine what we should do instead.

Here is wisdom: There are at least three techniques the efficient craftsman should employ, or at least develop skills adequate to deploy, when cutting joints in wood:

  1. Limit the amount of wood included in each cut to an amount easily and quickly cut and easily and quickly removed. Strict control of one’s inner-badger is required;
  2. Stop striking the chisel with hammer during each cut just before the chisel binds in a high-pressure situation, or just before waste clogs the joint. Once again, control of one’s impertinent inner-badger is essential.
  3. And then, without changing your grip on its handle, or losing a beat in your cutting rhythm, flick your wrist forwards or backwards so the chisel blade flips the waste out of the joint you are cutting without any silly levering.

And Voila! No time lost extracting a stuck blade or setting down and picking up your hammer and repositioning your grip on the chisel. And the cutting work can continue uninterrupted without the wasted time and effort of extracting a bound chisel all while avoiding a damaged cutting edge.

It’s very much a crisp dance step performed by hammer and chisel with a rhythm something like: “chop, chop, flick, (reposition chisel for next cut)… chop, chop, flick, (reposition chisel for next cut) … chop chop flick.” With each “flick” bits of cleanly cut wood fly out of the joint. I call this series of controlled movements the “ chisel cha cha.”

Next let’s examine the nexus between hammer weight and avoiding the dreaded chisel wiggle.

The Dance of the Hammer and the Chisel

Cha Cha

As mentioned above, the way to avoid the chisel wiggle and instead dance the more efficient and sophisticated chisel cha-cha is to avoid banging the chisel into the cut too deeply/tightly and to limit the waste made with each cut to an easily-removable amount. To dance this dance you need to stop hammering just before the blade binds in the cut, precisely controlling the depth to which your hammer drives your chisel into the wood.

Easy to say but difficult to accomplish if the hammer is too heavy. On the other hand, too light a hammer is also inefficient. Therefore, there is no one-size-fits-all-situations hammer weight.

A well-balanced, stable hammer with a handle that fits your hand/arm, and of a controllable weight makes it easier to develop and maintain this precise, unconscious control. Lots of factors are involved but the weight of the hammer/chisel combination is the most important one of the bunch.

How to determine the best weight? Of necessity it varies with the chisel, the type of cut being made, the nature of the wood being cut, and the nut holding the hammer so trial and error is the only practical solution. But generally, a hammer that feels a bit on the light side is best. And a good handle makes a world of difference. More on that in future posts, so stay tuned.

Summary

The following summarizes the points you should take away from this series of articles so far.

  1. Select a hammer weight that balances well with the width and weight of the chisel, the hardness of the wood you are cutting, your body, and the type of cuts you are making.
  2. The hammer should not be so heavy that you cannot precisely control the chisel’s depth of cut while maintaining an efficient cutting rhythm close to the natural frequency of the hand/arm/hammer assembly;
  3. Don’t drive the chisel so deeply into the wood that it binds forcing you to wiggle the chisel, or heaven forfend, demands wasteful movements like setting down your hammer to extract it;
  4. Use your sharp chisel for cutting wood, not as a crowbar for levering out waste. Instead, use your sharp blade to quickly cut the waste loose and then remove it from the joint by flicking your wrist without stopping, disrupting your cutting rhythm, or setting down your hammer.

By following these procedures you, your hammer, and your chisel will perform as a precise and graceful, but oh so violent team. Shall we dance?!

In the next installment in this tale of bold hammers and graceful chisels we will examine in more detail the rhythmical motions involved in doing chisel-work efficiently and the role of the hammer in that dance. Sorry, no champagne or pretty girls but there just might be a song or two. Until then, I have the honor to remain,

YMHOS

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Please share your insights and comments with everyone in the form located further below labeled “Leave a Reply.” We aren’t evil Google, fascist facebook, or thuggish Twitter and so won’t sell, share, or profitably “misplace” your information. May my chisel forever wiggle if I lie.

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Sharpening Part 27 – The Entire Face

A beautiful face: Oohirayama Lotus stone

If a dog will not come to you after having looked you in the face, you should go home and examine your conscience.

Woodrow Wilson

The subject of how to use the face of your sharpening stone is so basic and seems so unimportant that few give it the attention it warrants. But it is not trivial: it deserves its own post because it can truly make a big difference in the time and money you spend sharpening.

Money Down the Drain

Instead of focusing his attention on the blade alone, a wise man will make a conscious effort to use the entire face of his sharpening stone from edge to edge, end to end, and corner to corner instead of digging an oval swamp in the center of it’s poor abused face.

This habit will help to keep a stone’s faces flatter over more strokes longer, saving time truing the stone, and extending its life thereby saving money.

Remember that you paid money for the stone, the entire stone, not just the hollowed-out oval area in the center most people create when carelessly sharpening. How much of a stone do most people throw away? Idunno,… 20% maybe? Assuming this approximation is correct, just for the sake of illustrating a point, if you paid $100 dollars for the stone, that means $20 was turned into mud and washed away without providing Beloved Customer any benefit at all. And don’t forget the time you spent cutting down those high spots to keep the stone’s face flat. That makes it more than a $20 loss if you count your time worth anything, which you should.

Why not use the sides, ends and corners of the stone’s face too?

Developing Good Habits

When developing these intelligent work habits, it helps to cross-hatch the stone’s surface with a carpenter’s pencil to help you keep track of the areas you have not yet touched. Never fear, for while industrial diamonds are made from graphite, the form of graphite in pencil lead is still softer than the finest sharpening stone and won’t affect the sharpening process a bit.

Also, before and while sharpening, frequently use a thin stainless steel ruler to check the stone’s face lengthwise and crosswise at various locations, and of course on the diagonals to monitor wear. Don’t guess, lazy bones, examine. Between ruler and pencil you may discover you have developed less-than-efficient sharpening habits. With some thought you will also figure out how to change those habits so your sharpening efforts will be quicker and more cost-effective.

Before long, you will be able to detect uneven wear and warpage fairly reliably without using either tool as much, so stick with it until you do.

Hang Ten

One conundrum you have probably already discovered is that it is impractical to use the extreme right and left sides and both ends of the stone’s face to sharpen a blade. Or is it?

Here is wisdom: Teach yourself how to sharpen a blade’s bevel with one corner of the blade hanging off the stone part of the time, alternating evenly and frequently between right and left corners, of course. Strange as it may seem this technique is effective at not only keeping your sharpening stone flatter and making it last longer, but for keeping the cutting edges of your blades straighter. If this doesn’t make sense to you, think about it real hard. Then give it a try and you will see what I mean.

And since you are taking short strokes anyway, why not work the blade crosswise at the ends of the stone? A lot of expensive stone going to waste there, I’d wager.

I hate to sound like a broken record, but you will find that making short strokes will make it much easier to use the entire face of the stone.

If you feel this post needlessly states the obvious, or is “verbose,” allow me to remind Gentle Reader once again that the purpose of this blog is not to provide entertainment, sell stuff, troll for clicks or to trip and roll subscribers into Google Analytics’ s*thole, but to help our Beloved Customers develop good work habits through education. Some of them are newbies, and others are old hands, but if I were to write only for the professionals then I would be neglecting the newbies, so if you know this stuff already please congratulate yourself and celebrate your good fortune by buying a new carpenter’s pencil.

Related image

YMHOS

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Sharpening Japanese Woodworking Tools Part 1

Kinshiro Planes 金四郎鉋

Does the Japanese plane in the photo above look a little strange? It should. It’s a specialized plane for cutting decorative latticework used in traditional Japanese joinery and casework. There are more photos of this plane below.

We have a limited number of planes in-stock by a famous craftsman that used the brand name “Kinshiro” 金四郎 when he was active. This brand name translates to “golden fourth man.” It was once common in Japan to give male children names that reflected their order of birth.

Kinshiro is a Niigata Prefecture solo craftsman named Kuriyama Noboru 栗山昇. Born in 1932, he is the second generation in this line. The brand name came from his father’s name, “Kinshiro,” the first craftsman in the line, and reportedly a very severe master. Mr. Kuriyama retired in December 2011. 

Mr. Kuriyama specialized in making plane bodies, but made various other tools as well, including marking gauges, cutting gauges, and kudegoshi using blades provided by his distributor. Mr. Kuriyama’s dual-blade marking gauges (二丁鎌毛引き) are famous even outside Japan.

The blades were forged by a Niigata Prefecture blacksmith named Ishibashi Kenji, who has since left us for the big woodpile in the sky. Mr. Ishibashi used Aogami No.1 steel. I assume he used jigane from the same bridge in Yokohama that Niigata blacksmiths are still using today.

Small tool blades are a niche market served by specialist blacksmiths, so you may have not heard of Ishibashi Kenji-san before, but whatever you do, please do not mistake him with Ishibashi Toshichiro, a Niigata blacksmith who made standard plane blades and got in trouble for unknowingly making weapons for the Yakuza. Tsk tsk. Toshichiro’s blades were unimpressive.

Kinshiro’s products are well-known for their precision, functionality, extremely high quality and subtle style. We have been using Kinshiro products for many years with absolute satisfaction. They have always been expensive, but worth every penny. They have not decreased in value since his retirement.

Although new, and of course never used, these planes are old stock and a few of the blocks have some patina.

Most of them are extremely rare and are no longer made anywhere in Japan. When they are gone there will be no more. We wish we could hold onto them forever, but the time has come to release them into the world.

If you like rare collectable Japanese planes and appreciate exceptional craftsmanship, these will interest you. But don’t wait too long.

The Kinshiro planes we have in-stock are listed in the table below. Prices and more photos are the link below. Even if you aren’t interested in purchasing a Kinshiro plane, the photos are worth seeing. Be our guest. If you have questions please use the Questions Form below.

Link to Photos and Pricelist

ミニ組子 青海波 和風雑貨 インテリア 欄間サンプル タニハタ
ミニ組子 分銅輪つなぎ 和風雑貨 インテリア 欄間サンプル 組子欄間 タニハタ
Kinshiro PlanesWidth
Ireko moulding plane 入子面鉋27mm
Ireko moulding plane 入子面鉋36mm
Etemen Adjustable Chamfer Plane 猿面鉋 30mm 30 °/ 60°
Kiwaganna Skewed Rabbet Plane right hand36mm
Kiwaganna Skewed Rabbet Plane left hand36mm
Kiwaganna Small Skewed Rabbet Plane right hand single blade30mm
Kiwaganna Small Skewed Rabbet Plane right hand single blade15mm
Ovolo Moulding Plane 銀杏面鉋6mm
Ovolo Moulding Plane 銀杏面鉋9mm
Ovolo Moulding Plane 銀杏面鉋15mm
Flat Ovolo Moulding Plane 平銀杏面鉋5.4mm
Flat Ovolo Moulding Plane 平銀杏面鉋6mm
Flat Ovolo Moulding Plane 平銀杏面鉋12mm
Ogee Moulding Plane 瓢箪面鉋6mm
Ogee Moulding Plane 瓢箪面鉋7.5mm
Ogee Moulding Plane 瓢箪面鉋9mm
Ogee Moulding Plane 瓢箪面鉋12mm
Ogee Moulding Plane 瓢箪面鉋15mm
Ogee Moulding Plane 瓢箪面鉋18mm
Ogee Moulding Plane 瓢箪面鉋24mm
Roundover Moulding Plane 坊主面鉋4.5mm
Roundover Moulding Plane 坊主面鉋7.5mm
Roundover Moulding Plane 坊主面鉋9mm
Small Roundover Moulding Plane 豆坊主面鉋2mm
Round Moulding Plane 外丸鉋9㎜
Round Moulding Plane 外丸鉋12㎜
Round Moulding Plane 外丸鉋15㎜
Round Moulding Plane 外丸鉋18㎜
Round Moulding Plane 外丸鉋21㎜
Round Moulding Plane 外丸鉋24㎜
Round Moulding Plane 外丸鉋36㎜
Round Moulding Plane 外丸鉋42㎜
Hollow Moulding Plane 内丸鉋7.5㎜
Hollow Moulding Plane 内丸鉋9㎜
Hollow Moulding Plane 内丸鉋30㎜
45° Mitre Plane 留め鉋 (SOLD OUT)18㎜
Narrow Chamfer Plane 糸面鉋3㎜
Hanagata Kumiko Plane Square No.1 Extra-large 花形組子 角1号特大
Hanagata Kumiko Plane Round No.3 Large 花形組子 3号丸
Osaka Dado Plane 大阪作里18㎜

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Sharpening Part 26 – The Taming of the Skew

My relationship to reality has been so utterly skewed for so long that I don’t even notice it any more. It’s just my reality.

Ethan Hawke

The Taming of the Skew

Beloved Customer has of course noticed that it is easier to keep a blade stable when sharpening its bevel if you skew it on the stone. There is nothing wrong with skewing the blade so long as you understand the natural consequences of doing so and compensate for them appropriately. In this article we will examine some of those consequences.

The first and most immediately obvious consequence of skewing the blade when sharpening it is that the blade tends to wear-out, or hollow-out, the center area of the sharpening stone’s face quicker. This is inefficient, wasting time and stones, but can be compensated for if you pay attention and work the blade evenly over the stone’s entire face, including the edges, ends and those pesky corners. BTW, this is not a kindly suggestion but a commandment.

Second, skewing the blade usually results in the nut holding the blade placing uneven pressure on it, with the natural result that the blade wears unevenly, and quite often, develops a skewed cutting edge. Think about it.

In addition, the leading corner is exposed to more fresher, sharper, larger grit particles (which cut more aggressively) than the trailing corner. As a result, the blade’s leading corner tends to be abraded more, causing the blade’s edge to gradually become skewed or rounded in shape over many sharpening sessions. This is definitely bad, and is often mistaken for the work of those devilish iron pixies, especially in the case of kiwaganna and other skewed-blade planes, causing self-doubt, mental anguish, and even piranha in the head (aka “going bananas“). But if you are aware this can happen, and pay attention, you can easily compensate for this tendency thereby avoiding months of expensive psychoanalysis by Dr. Alonzo and the need to consume pallets of his pretty purple pills. 

Third, and I have no way to confirm this, I am told by the guys with microscopes that diagonal scratches at the extreme cutting edge leave it a tad weaker, causing it to dull just a bit quicker.

The way to remove problematic diagonal scratches, BTW, is to make the last few strokes on the finishing stone perpendicular to the cutting edge.

So in summary, habitually skewing a blade while sharpening it is not ideal and should be avoided, but is not catastrophic. It will make one’s sharpening efforts a little less efficient and may cause blades and stones to become distorted, but these negatives can be dealt with, at some cost.

Please read the quotation at the top of this article and consider whether or not your sharpening reality has become skewed without your realizing it. Your humble servant confesses, and Dr. Alonzo can confirm, that his was indeed skewed for a long time.

These aren’t things you wouldn’t have figured out for yourself eventually, Beloved Customer, but now, at least if you pay attention, you’re a few years ahead on the learning curve. In the worst case, at least ignorance isn’t an excuse anymore. And there’s always those pretty purple pills to take the edge off (ツ).

YMHOS

Related image
Shakespeare’s Shrew, Katherine Minola, played by Elizabeth Taylor in the 1987 movie. In this photograph she’s obviously watching someone skewing a plane or chisel blade while sharpening it. Clint Eastwood probably learned a thing or two about squinting from this lady.

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.

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The Challenges of Professional-grade Japanese Chisels

Japanese Planes – Mitre Plane 留鉋

道具屋の展示会で掘り出し物に出会うの巻。
#wood #woodworking #woods #金四郎 #留鉋#当時の値段#バイブス#宍戸建具店 #南相馬市#鉋
A Tomeganna Plane by Kinshiro (Kuriyama Noboru)

This is a brief post about an unusual Japanese plane made by an unusual craftsman and used in an unusual way, or at least one not seen often in the West.

The plane is called the “Tome ganna” written 留鉋 which means “mitre plane.” In this case, mitre does not necessarily mean just a standard 45 ° mitre as in a picture frame corner, but the planes pictured above are indeed intended to cut a 45 ° mitre for corner joints between two boards.

It is specialized for cutting a critical part of the secret dovetail mitre joint used for casework, and is a standard tool for cabinetmakers and sashimonoshi in Japan.

The plane rides on its beveled sides when shooting the mitre joint.
This page has illustrations of how to cut this joint the Japanese way using this plane. 

This job can be done using jigs and chisels, shoulder planes, or better yet, kiwaganna, but the tomeganna is better balanced and handier, can cut either direction more precisely and quicker, so is a must-have for advanced casework.

If you enjoy casework, the secret dovetail mitre is a challenging joint you really should give a try. The results are great fun, even if they aren’t flashy. 

The excellent Mr. David Charlesworth has even produced a video sold by Lie-Nielson about how to make this joint, although he uses a jig and a paring chisel to good effect.

This is a link to a pricelist and pictures of our limited number of planes by the famous craftsman Kinshiro. You might find the story and photographs interesting.

YMHOS

If you have questions or would like to learn more about our tools, please use the questions 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 or incompetent facebook and so won’t sell, share, or conveniently and profitably “misplace” your information.

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Hammers to Use With Chisels Part 3 – Hammer Weight

Top: 375gm Yamakichi gennou head by Hiroki with new osage orange handle. Bottom: Ryoguchi-style gennou head by Kosaburo with a seasoned handle of the same osage orange. This same hammer was shown in Part 1 of this series when it was fresh and nuclear-flash yellow. With time and exposure to sunlight the color has changed to this pleasant brown. Thanks Matt for the OO!

“All that is gold does not glitter,

Not all those who wander are lost;

The old that is strong does not wither,

Deep roots are not reached by the frost.

From the ashes a fire shall be woken,

A light from the shadows shall spring;

Renewed shall be blade that was broken,

The crownless again shall be king.

J.R.R. Tolkien, The Fellowship of the Ring

In previous articles in this series about hammers to use with our chisels, your most humble and obedient servant discussed the varieties of hammers and the types of faces suitable for using with our chisels. In this article we will examine not only hammer weights but other factors to help your chisel work go more efficiently.

Beater & Beatee

You can usually tell when a hammer is too light for the job because the chisel or nail isn’t moved much and the beater bounces off. But it’s the other end of the weight scale that causes more serious problems so let’s consider the case of too heavy hammers so we can bracket the Goldilocks weight: Not too heavy, not too light, but just right.

Some people like to use heavy hammers for striking chisels. 2~3-lb ox-killers are good for some jobs, but there are a few things you should consider before defaulting too such a heavy lump.

Is the impact force produced by a heavy hammer really necessary to drive a chisel? Too often not so much. But not everything we do must focus exclusively on efficiency: swinging a hammer is good exercise and it burns calories, something those with excess “ dignity,” such as your humble servant, could use more of. However, in light of other factors discussed below, I urge you to resist the natural compulsion to remain one of the “beautiful people” by maintaining at all costs a sylphlike figure worthy of Paris Fashion Week by obsessively using overly-heavy hammers. Relax, for you already look mahvelous, darling, absolutely mahvelous!

Besides the herculean strength of your mighty arm and the chisel’s durability, Gentle Reader should also consider the durability of your body. Swinging a hammer that is too heavy can over-stress muscles, tendons, bones and joints, stresses that can make workdays long, nights painful and your work sloppy, if not now then certainly as you age. More on that subject in a future article.

But if the weight of the head is a good balance with the work you are doing, and you have a good handle on your hammer or gennou, things just go better. We will look at this more in the final post in this series.

Let’s start at the beginning and consider the movement of the hammer and the forces generated when accelerating it towards nail or chisel and the resulting stresses produced in muscles, tendons, bones and joints. Obviously, it is wise to keep these stresses within acceptable limits, especially if you need to repeat this movement hundreds or even thousands of times in a day. It should likewise be obvious that a hammer that is overly heavy makes limiting these stresses difficult.

Now that we have the hammer moving, let’s examine what happens when it stops as it strikes nail or chisel. Is wacking the nail or chisel as hard as possible the goal, or is the goal to drive the nail into the wood the right depth, or to motivate the chisel to cut wood an appropriate distance? If the latter, then there is a practical limit to the impact force required.

In other words, does driving a nail so deeply the wood is damaged unnecessarily, or does wacking a chisel so hard it cuts all the way through the board, or even binds in the wood, help us do better work?

Are the excessive stresses and vibrations flowing and slamming through one’s joints and tendons as a result of the violent acceleration, deceleration and impact forces generated when swinging an overweight hammer healthy and helpful? Or do they just waste energy, damage our work product, cause bruising, pinching, grinding and numbness and generally wear out hands and arms? Do these excessive stresses and vibrations improve our precision?

The positive and negative results of using a hammer are easier to control if the hammer’s weight is balanced with our bodies, the nail or chisel, and the wood.

Another factor to consider is the nature of the beatee. Nails often suffer from hammer abuse, but they don’t have feelings or form mutual support groups with monthly meetings and free coffee and donuts, while chisels do, so I encourage you be sensitive to your chisel’s needs when selecting a hammer weight. Oh, and don’t forget to donate a box of fresh donuts occasionally (with sprinkles).

Our chisels are hand-made professional-grade tools intended to be used by craftsmen who demand the extra sharpness and cutting longevity only hard, fine-grained steel makes possible. Therefore they are not as tough as the soft, sharpened Chinese screwdrivers sold by the big corporations as chisels that amateurs are accustomed to nowadays. Accordingly you should select a hammer weight that won’t damage the blades or splinter the handles of your fine chisels even if you must use them all day for days on end hard enough for the impact forces to make the handles hot. You may be as strong as John Henry, but a 2-lb hammer will destroy most any chisel given time and determination.

Weighty Matters

Of course, the harder the wood, the deeper the cut, the wider and heavier the chisel, the heavier the hammer needed. But what is an efficient hammer weight? Let’s consider some guidelines.

Oiirenomi & Mukomachinomi Chisels

For most commercially-available woods you are likely to cut with your oiirenomi chisels or mukomachinomi (mortise chisel), 260gm/9oz/70monme is a good place to start when using narrower width chisels 18mm and less.

300gm (10.5oz/80monme) to 375gm (14oz/100monme) is probably good for wider chisels. BTW the standard carpenter’s hammer in Japan weighs between 375gm (14oz/100monme) to 450gm (16oz/120monme), but this is too heavy for most precision work using oiirenomi in furniture, cabinets, and joinery work.

Atsunomi Chisels

For the heavier atsunomi chisels from 18mm to 24mm in width, 375gm (14oz/100monme) ~ 450gm (16oz/120monme) is usually a good weight.

For wider atsunomi chisels, 675gm (24oz/180monme) to 750gm (26oz/200monme) is good. Maybe as heavy as 937gm (32oz/250monme) for motivating wide 48-54mm chisels when cutting hard woods if you have experience, strong wrists, and speed is not important. Yes, within limits and with a good handle, lighter weight hammers tend to accomplish more work quicker.

As Captain Barbossa explained the Pirate’s Code, these are “more what you’d call “guidelines” than actual rules.”

In future posts in this series we will examine factors such as how to use hammers and chisels efficiently, and how to avoid injuries.

Until then, I have the honor to remain,

YMHOS

PS: We have also published another series of articles about making a handle for your hammer that fits your body and will work most efficiently for you, beginning HERE. So let’s talk some more soon.

Harrrrg. Your hammer’s how heavy?!

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 fingers become beatees.

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Sharpening Part 25 – Short Strokes

Festina Lente Doors in the Palazzo Vecchio, Florence, Italy

Long-term consistency beats short-term intensity.

Bruce Lee

We have discussed many details about sharpening in this series, and while this may be the shortest article of the bunch, it is by no means the most insignificant. For some it will be the most difficult technique to master, so classical references shouldn’t prove too onerous.

If Beloved Customer pays attention to their blade’s movement when sharpening, you will notice how each reversal of direction tends to cause the bevel to rock forward and backward on the stone’s face. And what happens when we let the blade go rock-n-rolla? That’s right, the crapulous bulging bevel rears its ugly head and spits stinky sticky stuff in our eye.

Using short strokes, somewhere around 1-½ inch in length, makes it much easier to keep the blade from rocking.

A Gentle Reader named Oskar observed that, following the logic in the previous sentence, shorter strokes result in more, not less, reversals in stroke direction, and therefore shorter strokes should lead to more rocking rather than less. I concur with Oskar’s analysis and conclusion, as far as it goes, and am adding the following clarification to avoid confusion.

A short stroke produces smaller changes in the angles of one’s joints during the stroke compared to the changes during a longer stroke, making it much easier to maintain the bevel at the correct angle on the stone’s face. In other words, the angles of the joints in hand, wrist, arm and shoulder change less during short strokes than in longer strokes, making it easier to manage joints and tendons yielding greater repeatability.

In addition, shorter strokes tend to focus one’s attention on properly indexing the bevel on the stone during each individual stroke, attention that tends to wander more during long strokes. It’s that darn badger again.

鑿研ぎ #14_e0248405_1553630.jpg

Please note that this analysis is simply your humble servant’s opinion, and perhaps not a weighty one at that because I am not a physician, nor have I conducted the physiological studies and dissections upon which a rigorous opinion should be based.

I know that making short strokes feels inefficient, and it is compared to a machine, but Beloved Customer is probably not a Cyberdyne Systems product with a titanium alloy combat chassis. However, with practice, you will find you are able to increase the distance and speed of each stroke, especially as your focus and hand-soul coordination improves and your wrists and elbows relax and become trained.

Long extravagant strokes on rough or medium grit stones are for sharpening axes and kitchen knives, not chisels or planes.

The exception to this rule is the finishing stone, as mentioned in the previous article.

Festina Lente

In conclusion, and in order to improve your classical education, let’s review our latin lesson from the previous article: “Festina lente” translates directly as “make hast slowly.” It is defined in the dictionary as “proceed expeditiously but prudently.” We chose to translate the phrase as “Slow is smooth; Smooth is fast. ”

At least two Roman emperors, one Pope, and the powerful Medici family of the City State of Firenze Italy, back in the days when emperors, popes, and noble merchants had real power measured in armies they controlled and cities and continents they ruled, thought these two words important enough to include in their mottos and coats of arms. The words even appear in the original French version of the tale of the “Hare and Tortoise.”

They are also relevant to sharpening if you are clever enough to understand why.

YMHOS

Bug-nibbled woodwork in the Laurencian Library in Florence Italy with the Medici’s motto of Festina Lente and the turtle with a sail carved into it.

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 my food turn to ashes in my mouth (a very ancient curse indeed).

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Other Relevant Posts

The Challenges of Professional-grade Japanese Chisels

Sharpening Part 24 – Sharpening Direction

Related image

If you do not change direction, you may end up where you are heading.

Lao Tzu

When using rough stones ( ≤1000grit), and especially when learning basic sharpening skills, it is best to sharpen the bevel in one direction only, lifting the blade off the stone, or at least removing all downward pressure, on the return stroke. The reason for this seemingly inefficient movement is simply that, at least for most people, and until one’s hands and wrists beceome trained, trying to abrade the blade on both push and pull strokes is likely to cause the blade to rock creating the bilious bulging bevel.

There are certainly exceptions to this rule, and we actively encourage Beloved Customer to try to develop the concentration and muscle control required to sharpen in both directions on rough and medium stones, but be aware it may take some years. In the meantime, remember the ancient adage and imperial moto: festina lente, which we chose to translate as “Slow is smooth; Smooth is fast. “

Part of the difficulty of sharpening in both directions is the resulting loss of concentration: the swing of the thing and angle of the dangle are hard to sense. Perhaps another part of it is due to the difficulty of controlling the complicated and constantly-changing angles of bones and joints. Both of these natural mental and physical tendencies can be overcome by talented and determined people given time and daily practice, but in the case of everyone your humble servant has ever spoken with on the subject, it takes years of focused on-the-job practice, and extreme concentration at first to overcome pre-existing bad habits and to avoid developing importune muscle memory.

Which Direction?

At this point you need to make a decision, unless you have already made it inadvertently. That is, whether to sharpen on the push stroke (pushing the blade away from you) or on the pull stroke (pulling the blade towards you). Most people choose the push stroke, as do I, but in reality the pull stroke is actually a little more efficient because the pressure tends to focus closer to the bevel’s front instead of back, and rocking is reduced. Whichever direction you choose, use it consistently.

However, as mentioned in previous articles in this series, and this is critically important, when it comes to the final finishing stone, work the blade back and forth in both directions. The finishing stone is not abrasive enough to change the bevel’s shape, and since you need to polish the last few microns width of blade’s cutting edge, a very tiny amount of unintentional rocking is actually helpful.

Training Techniques

If Beloved Customer is determined to develop the ability to sharpen on both push and pull strokes, your humble servant can share some helpful guidance that was given to me many years ago by a sword polisher.

The first step in training yourself is to begin by lifting the blade from the stone’s surface entirely on the return stroke (either push or pull depending on your preferred direction). All the things mentioned above apply. Becoming proficient with this technique is foundational. Strive to project your senses into the blade traveling over the stone, indeed right down to the last few microns of the cutting edge, becoming Zen Master Bubba.

When you are able to create a sharp edge while maintaining a flat bevel consistently and without much concentration using this “one-way” technique, then move on to the second step, which is to keep the blade in contact with the stone on the return stroke, but relieve all downward pressure. Begin slowly with full concentration and strive for smooth motion. It’s at the transition from one direction to the other where Murphy will toss a banana peel under your heel.

And finally, when you have mastered the “light-touch” technique, try applying downward pressure in both directions, beginning slowly at first and with full concentration striving for smooth motion.

Remember, don’t grip the blade like a thrashing alligator, but hold it lightly in your hands like a small bird: too tightly and it will be crushed; too loosely and it will fly away.

Don’t lock your wrists or elbows, but actively and consciously rotate them to keep the blade’s bevel always perfectly flat on the stone (your stone is flat right, right?). This is very important.

And don’t forget to use your thin stainless steel straightedge and brass bevel gauge frequently to check the bevel for flatness and proper angle.

And as always, relentlessly beat down your inner badger, brutally crush and sow salt on bad habits, and don’t allow new bad ones to take root.

Sadly, this is a skill that, once learned, tends to deteriorate with time unless practiced frequently. As with cherry blossoms, muscles, tendons and eyes are neither static nor eternal. Setsunai, desu ne.

YMHOS

If you have questions or would like to learn more about our tools, please click the “Pricelist” link here or at the top of the page and use the “Contact Us” form located immediately below.

Please share your insights and comments with everyone in the form located further below labeled “Leave a Reply.” We aren’t evil Google, fascist facebook, or thuggish Twitter and so won’t sell, share, or profitably “misplace” your information. If I lie may my wife be plagued with runners in her hose.

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Hammers to Use With Chisels Part 2 – Hammer Faces

The Jabberwock! Not just a beautiful face.

Beware the Jabberwock, my son!
      The jaws that bite, the claws that catch!
Beware the Jubjub bird, and shun
      The frumious Bandersnatch!

Lewis Carroll

This is the second post in our six-part series about hammers to use with our chisels. As with all the tool-related articles we publish, this one is based on past communications with, and in response to direct questions from, our Beloved Customers. Your humble servant hopes that not only Beloved Customers (may the hair on their toes never fall out) but Gentle Readers too may gain something from these articles.

We sell limited quantities of hand-forged professional-grade chisels to professionals who use them to please their customers and feed their families.

We are tickled pink when amateurs purchase our products, but our target customer is the experienced professional woodworker. If you do your part our chisels will provide faithful, reliable service until, after many decades, nothing is left of the blade but a nub. But to achieve this longevity, and to avoid smiles turning upside down, we insist Beloved Customers use flat-faced hammers to motivate our chisels as a condition of our warranty. It’s that important, at least for the professional that uses his chisel even after the blade and handle become hot.

375gm gennou by Kosaburo with a black Persimmon handle resting on a Go board. The head is a classical style seldom seen nowadays.

In the previous post in this series we looked at the Japanese gennou hammer with its two faces: one domed and the other flat. In this post we will examine these two styles of hammer faces in more detail. We will leave waffle-faces to the Belgians for now.

The Domed Hammer Face

Few people in industrialized countries outside of Japan have any experience with flat-faced hammers since manufacturers automatically grind a convex or domed striking face on their hammers nowadays. It’s simply what consumers are accustomed too. But I daresay few have ever considered the ramifications of the dome.

Does the domed face on this standard 16oz American finish hammer look centered to you? Does it look smooth?

A domed face on a hammer has some advantages, of course. For instance, when one needs to “set” a nail with its head just below the flat surface of the piece of wood into which the nail is driven. But does a domed face help the hammer drive nails faster or straighter? Does it help reduce the ratio of bent nails to straight nails? Does it motivate chisels more efficiently? No, no and no.

Another more questionable feature of the domed face (depending on your viewpoint) is that it makes it difficult to judge the accuracy of one’s alignment of the centerpoint of the domed face and with the centerline of the hammer head. Who, pray tell, profits from this ambivalent construction? I’ll give you one guess, and it ain’t me or thee.

Indeed, if your working hammer tends to bend a lot of nails, I recommend you carefully examine its face with a square for centricity and uniformity. “Doh! (palm to forehead). No frikin wonder,” may well be your genteel reaction.

While it may seem passing strange, we strongly recommend Beloved Customers use a hammer with a flat striking face to motivate our oiirenomi chisels, atsunomi chisels, and mortise chisels.

So why is a domed-face hammer a problem when striking Japanese chisels? Simply because it tends to focus the impact forces on a relatively smaller area on the wooden handle than a flat-faced hammer does accelerating wear on, and shortening the life of, the handle.

In addition, and especially if you are skilled at hitting the handle dead-center a high percentage of the time, a domed face will actually encourage the mild-steel crown to try to jump off the handle whereupon the steel hammer gleefully beats the crown and deforms it, often to the point where the deformed crown itself may damage the handle. Yes, this takes some time, but it happens frequently, a wasteful tragedy that can be avoided by using a hammer with a flat face and some simple setup procedures.

The Flat Hammer Face

While your humble servant is inordinately fond of the Japanese gennou hammer, it is by no means the only viable option. Indeed, you can easily modify most any decent-quality, properly-hardened hammer to have a flat face by simply abrading it with a grinder or sander.

Be sure you make the new face planar (flat) and truly square to the hammer’s centerline because a tilt to the left or right will make doing precise work inexplicably difficult and may lead to insanity. I once knew a “frugal” carpenter (read “cheap jackass”) who insisted on using a hammer with a skewampus face. The cumulative corrosion to his confidence caused his wits to wander into the weeds (iambic pentameter?). A sad story but one, I am told, that is commonly heard at AA meetings.

If you are modifying a standard hammer with a standard handle, you may benefit from tilting the face’s plane a bit inwards towards the handle, but there is not adequate space in this post to discuss this modification in detail.

Whatever you do, be especially careful to avoid overheating the hammer’s face while grinding/sanding it; Too hot and the temper will be damaged softening the hammer’s face and ruining it. Seriously. Even a wooden chisel handle will eventually mushroom a steel hammer that has lost its temper.

Here’s a guideline: If the hammer’s face becomes too hot to touch with your bare finger, its temper is at serious risk.

Finally, once the face is as flat and square and smooth as you can make it with your grinder or sander, be sure to polish the face because a smooth face wears out the chisel handle slower. A final polish with 320 grit W/D sandpaper is adequate. We polish ours even finer on sharpening stones. Overkill? Yup. Why bother? Because we like purty hammers and they deserve our love. Don’t worry, the polish won’t make the hammer’s face slippery, unless you imitate Mr. March Hare and spread butter on it.

By the way, once your flat-face hammer is ready, try driving nails with it. You will find it works a lot better for everything except setting nailheads below the board’s face. A nailset works better for that job anyway.

We hope our Beloved Customers will take this article to heart for the sake of their chisels.

Summary

In this post we reviewed two types of hammer faces: domed and flat. We also considered the advantages and disadvantages of each, and explained why a flat face is best for beating on Japanese chisels, and gave an example of the brutish damage a domed face can inflict on a poor innocent chisel. Like me, some of you may have shed a tear at the sight, but I bid you take heart because we also instructed you in how to convert a common domed-face hammer of any sort to a more genteel, polished, flat-faced hammer at no cost, one that will also drive nails better without butter. O frabjous day! Callooh! Callay!

To motivate chisels efficiently, the hammer must not only have a flat face, but it must be of the appropriate weight. Of course, the harder the wood, the deeper the cut, the wider and heavier the chisel, the heavier the hammer needed. But what is an efficient hammer weight? We will examine some options in the next post in this series. Please stay tuned, my beamish boy.

Until then, I have the honor to remain,

YMHOS

A hand-forged square gennou head by Hiroki with a handle made from a traditional Japanese handle wood called “Kamatsu” (Pourthiaea villosa) meaning “sickle handle, also called “Ushikoroshi (“cow killer”). Despite the appearance, the head is one-piece of uniform steel, not a jigane body with forge-welded steel faces. BTW, if someone tells you that hammers with forge-welded faces are superior, direct them to the closest legal marijuana dispensary so they can maintain their waking psychotic dreams.

If you have questions or would like to learn more about our tools, please click the see the “Pricelist” link here or at the top of the page and use the “Contact Us” form located immediately below.

Please share your insights and comments with everyone in the form located further below labeled “Leave a Reply.” We aren’t evil Google, fascist facebook, or thuggish Twitter and so won’t sell, share, or profitably “misplace” your information. If I lie may a Bandersnatch fruminate all over my face!

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