The Varieties of Japanese Chisels Part 5 – High-Speed Steel Oiirenomi (HSS 追入鑿)

“Life is not a matter of holding good cards, but of playing a poor hand well.” – Robert Louis Stevenson

So, you finished building that fine cabinet, or 8-panel entry door, or carved balustrade and the day has come to install it at the jobsite. Will you need to cut a bit of gypboard or lath-and-plaster while installing it? Might your chisel get jammed against or into bricks or concrete in the process? Will you need to cut a notch in sandpaper-grit filled plywood or OSB? Any hidden screws or nails in the way that might require more than stern words?

Jobsite installations and remodeling often demand nasty work everyday tools can’t accomplish without serious damage. At that moment, having a tool tougher than the job is the difference between working and whining. This is that tool.

DESCRIPTION

HSS oiirenomi are a modern variation of mentori oiirenomi made using high-alloy steels tougher and more resistant to abrasion and high temperatures than more traditional steels.

Sukemaru High-speed Steel Oiirenomi

These chisels are useful for doing remodeling work and cabinet and equipment installations where plywood, MDF, OSB, LVL, drywall, acoustic board, insulated board, plaster, mortar, underlayment and studs full of hidden nails, and even ALC (autoclaved lightweight concrete) panels need to be cut, trimmed, fitted or demolished. Demolition…Oh joy (not).

Although High Speed Steel (HSS) won’t become as sharp as plain high-carbon steel, and takes more time to sharpen using a grinder and diamond plates, when you need to cut or trim the hard abrasive materials listed above, these blades will keep clippin’ without chippin’ when a standard chisel would be turned into an expensive gasket scraper. Also, one can quickly repair the damaged edge on an HSS chisel with a bench grinder or angle head grinder of the sort found on any construction jobsite without burning or softening the steel, a handy feature indeed.

HSS oiirenomi are hardened using special processes that leave the metal bright instead of creating the black oxide skin typical of standard high-carbon steel blades, an appearance some people find attractive.

Before I tried my first HSS oiirenomi, I kept a couple of old plastic-handled steel-cap Stanley chisels in my toolkit as “beaters” for cutting gritty, abrasive materials. They were soft and instantly dulled, but their edges would dent instead of chipping and were easily repaired. Poor things; some days they ended up looking more like rounded-over wide-blade screwdrivers than wood chisels. HSS chisels are just the ticket for this kind of brutal work.

The chisel pictured above was manufactured by Mr. Usui Yoshio under his brand “Sukemaru” (助丸). He is the fourth generation in this long line of famous blacksmiths.

The blade is one-piece of high-speed steel, not laminated high-carbon steel. The neck, however, is a softer, more malleable stainless steel which adds toughness to the tool while reducing costs.

Interestingly, the blade and neck are not welded together, but are connected by spinning the neck at high speed and forcing it against the stationary blade fusing the two components together more securely than is possible by welding. An amazing sight to see. High-level mechanical engineering going on here, boys and germs.

Standard widths for high-speed steel oiirenomi are 3mm, 6mm, 9mm, 12mm, 15mm, 18mm, 21mm, 24mm, 30mm, 36mm, and 42mm.

YMHOS

Links to Other Posts in this Series

The Varieties of Japanese Chisels Part 1 – The Main Categories

The Varieties of Japanese Chisels Part 2 – The Mentori Oiirenomi (面取追入鑿)

The Varieties of Japanese Chisels Part 3 – The Shinogi Oiirenomi (鎬追入鑿)

The Varieties of Japanese Chisels Part 4 – Kakuuchi Oiirenomi (角打追入鑿)

The Varieties of Japanese Chisels Part 6 – The Mortise Chisel (Mukomachi Nomi 向待鑿)

The Varieties of Japanese Chisels Part 7 – The Nihon Mukomachi Nomi (二本向待鑿)

The Varieties of Japanese Chisels Part 8 – The Atsunomi (厚鑿)

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

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

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

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

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

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

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

If you have private 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.” Your information will remain confidential (we’re not evil Google or incompetent facebook).


The Varieties of Japanese Chisels Part 4 – Kakuuchi Oiirenomi (角打追入鑿)

“Do not wait; the time will never be “just right.” Start where you stand, and work with whatever tools you may have at your command, and better tools will be found as you go along.”

George Herbert

The oldest style of oiirenomi currently available nowadays is called ” kakuuchi oiirenomi” (角打追い入れ鑿)which means ”square-forged oiirenomi,” refering to the squarish shape. In cross section, the blade is rectangular with 4 more-or-less square outside corners. Other than this cross-sectional detail, it is identical in appearance to the mentori oiirenomi we discussed in my earlier post here.

Kakuuchi Oiirenomi – Hidari no Ichihiro (Hyotan mark)
Kakuuchi Oiirenomi – Hidari no Ichihiro (Polished; Hyotan mark)
Kakuuchi Oiirenomi – Hidari no Ichihiro (Hyotan and “Mi” marks)

DESCRIPTION

Where the Shinogi Oiirenomi in the previous post is thin and light, the Kakuuchi Oiirenomi is bulkier and heavier. They are also stiffer in the blade and even in the neck, which can be an advantage in narrower widths.

This added stiffness is not due to the extra mass of metal alone, but also to the fact that the steel layer is wrapped further up the blade’s sides than is possible for the thinner beveled sides of the mentori oiirenomi, as you can see in the photos above. Wrapping the high-carbon steel cutting layer up the blade’s softer low-carbon steel sides in this way creates in effect a hardened steel “U” channel with an increased moment of inertia, which makes the blade much stiffer. The thicker the chisel’s sides, and the deeper the U channel, the stiffer the blade will be.

The U-channel construction of Japanese chisels is a clever but subtle structural detail unique in the universe of chisels and one most people are not aware of.

Carving chisels do not have this U-channel detail and therefore are not as stiff or as tough as chisels that do. When you are considering buying a chisel, this is an important feature to confirm.

The following are some pictures of two of our Kakuuchi Oirenomi by Nagamitsu, hand-forged, of course, from Hitachi Yasuki Shirogami No.1 Steel (aka “White Steel).

36mm Kakuuchi Oiirenomi by Nagamitsu (Face)
36mm Kakuuchi Oiirenomi by Nagamitsu (Side)
12mm Kakuuchi Oiirenomi by Nagamitsu (Ura)
36mm Kakuuchi Oiirenomi by Nagamitsu (face)
36mm Kakuuchi Oiirenomi by Nagamitsu (Side)
36mm Kakuuchi Oiirenomi by Nagamitsu (ura)

Kakuuchi chisels take less time for a blacksmith to shape than the mentori oiirenomi we discussed in Part 2 of this series. The difference in shaping these two styles of chisels is the added step of grinding the extra bevels that make the mentori oiirenomi sleeker.

Indeed, most styles of Japanese chisels can be obtained with a kakuuchi cross section, including the oiirenomi version shown in my previous post, as well as atsunomi and usunomi, chisels we will examine in future posts.

Kakuuchi-style chisels take a little more effort to sharpen because the area of the bevel is larger, and more significantly, the area of the hard steel layer is greater, but on the other hand, they feel more stable on the stones.

More than a preference for greater weight, stiffness and stability, I suspect most individuals who prefer this old-fashioned chisel are making a fashion statement, something like “brogues not oxfords,” if I can adapt a movie quote.

In my opinion, they are not as elegant in appearance nor as handy as either the mentori oiirenomi or shinogi oiirenomi referenced in previous posts, but they do have undeniable dignity and presence.

What do you think?

YMHOS

Links to Other Posts in this Series

The Varieties of Japanese Chisels Part 1 – The Main Categories

The Varieties of Japanese Chisels Part 2 – The Mentori Oiirenomi (面取追入鑿)

The Varieties of Japanese Chisels Part 3 – The Shinogi Oiirenomi (鎬追入鑿)

The Varieties of Japanese Chisels Part 5 – High-Speed Steel Oiirenomi (HSS 追入鑿)

The Varieties of Japanese Chisels Part 6 – The Mortise Chisel (Mukomachi Nomi 向待鑿)

The Varieties of Japanese Chisels Part 7 – The Nihon Mukomachi Nomi (二本向待鑿)

The Varieties of Japanese Chisels Part 8 – The Atsunomi (厚鑿)

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

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

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

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

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

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

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

If you have private 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.” Your information will remain confidential (we’re not evil Google or incompetent facebook).

The Varieties of Japanese Chisels Part 3 – The Shinogi Oiirenomi (鎬追入鑿)

“The best investment is in the tools of one’s own trade.”

Benjamin Franklin

The next variety of oirenomi we will look at is called the ”shinogi oiirenomi” (鎬追入鑿).

Hidari no Ichihihiro Shinogi Oiirenomi Blade
Shinogi Oiirenomi – Nagamitsu 長光

Shinogi (鎬) means ”ridge” as in the angled ridge of a rooftop or mountain. It is pronounced “she-noh-gee.” I believe the word was borrowed from the sword world where it refers to an angled ridge design on the back edge of Japanese swords (shinogizukuri 鎬造り). This detail is used not only in tatakinomi but in tsukinomi as well.

鎬が高い図
Two Angles of Sword Shinogi
日本刀の断面図
Blade Cross-section
View of Sword’s Shinogi and Hamon

Shinogi oiirenomi are beveled like mentori oiirenomi but are different in that the bevels extend all the way to the centerline of the blade’s face creating a definite ridge. The thickness of the blade’s right and left edges is typically thinner than oiirenomi making it easier to get into tight corners.

I am very fond of this handy, lightweight style of oirenomi and keep a 10pc set mounted to the inside of my toolchest’s lid.

The downside to this design is that the chisel blade loses some stiffness compared to other styles, so they are less than ideal for heavy-duty wood hogging.

Some call these ” umeki” or ” dovetail” chisels. Indeed, some blacksmiths will grind the bevels to a very thin edge for this purpose.

My blacksmiths will not create these thin edges for three reasons: First, shinogi oirenomi are not all that rigid to being with, and thinning the sides further is inviting breakage. Second, warpage is especially difficult to control in thin cross-sections resulting in more rejects and increased costs. And third, people always cut themselves badly using chisels with sides made thin enough to actually fit dovetails. Neither my blacksmiths nor I want that responsibility.

Most umeki chisels do not have the thin sides most people expect.

If you need very thin, sharp sides, you should grind and polish the bevels yourself. Don’t forget to keep a first-aid kit close by, one you can use with just one hand. Seriously.

Shinogi oiirenomi are available in the same widths as oiirenomi.

In the next post I will introduce an old-fashioned but still useful oiirenomi called the “kakuuchi oirenomi.” Stay tuned.

YMHOS

© 2019 Stanley Covington All Rights Reserved

Links to Other Posts in this Series

The Varieties of Japanese Chisels Part 1 – The Main Categories

The Varieties of Japanese Chisels Part 2 – The Mentori Oiirenomi (面取追入鑿)

The Varieties of Japanese Chisels Part 4 – Kakuuchi Oiirenomi (角打追入鑿)

The Varieties of Japanese Chisels Part 5 – High-Speed Steel Oiirenomi (HSS 追入鑿)

The Varieties of Japanese Chisels Part 6 – The Mortise Chisel (Mukomachi Nomi 向待鑿)

The Varieties of Japanese Chisels Part 7 – The Nihon Mukomachi Nomi (二本向待鑿)

The Varieties of Japanese Chisels Part 8 – The Atsunomi (厚鑿)

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

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

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

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

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

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

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

If you have private 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.” Your information will remain confidential (we’re not evil Google or incompetent facebook).

The Varieties of Japanese Chisels Part 2 – The Mentori Oiirenomi (面取追入鑿)

42mm Hidarino Ichihihiro Mentori Oirenomi, a beautiful sculptural chisel by a renowned blackmsith, Mr. Yamazaki (RIP)

The Oiirenomi (pr0nounced Oh-ee-reh-no-me) is the most common variety of Japanese woodworking chisel, and the style best known both inside and outside Japan. There are several types of oiirenomi. In this post we will look at the most popular type of oirenomi called the ”mentori oirenomi” ( 面取り追入鑿) meaning ” beveled” oirenomi.

DESCRIPTION

As mentioned in my previous post in this series, nomi means ” chisel, ” but the term ”oiire” 追入れ” is not so straightforward. It is composed of two Chinese characters: ”Oi” 追いmeaning ”to chase” or ” to follow,” and ”ire” 入れ meaning ” insert” or ”place in.” I am uncertain of the origin of this word, but some hints of the original meaning may perhaps be deduced from the characters.

As the name suggests, this chisel’s face is beveled at both sides making it lighter and better able to get into tight locations than the older-style kakuuchi oiirenomi, the forerunner of this chisel, which we will examine in a future post.

I think most people agree that the two bevels moving up the blade, curving around the shoulder, and feathering into the neck give this chisel a sculptural, elegant appearance. The bevels do sacrifice some stiffness and authority compared to the kakuuchi style, but clearly, these compromises are acceptable to most consumers.

APPLICATIONS

A member of the tatakinomi family, it is designed to be struck with a steel hammer and has a hoop (called a “katsura” in Japanese which means “crown”) on the handle’s end to prevent splitting.

There are larger types of tatakinomi called atsunomi better suited than the oiirenomi to heavy cutting and wasting wood in applications such as timber frame joints, and most of those share the same mentori bevel detail, but oiirenomi are better suited to lighter tasks such as furniture work and interior installation work the same as Western bench or butt chisels.

Oiirenomi in general and mentori oiirenomi especially are light-weight, relatively inexpensive, and handy to use. All woodworkers in Japan own at least a few of these.

Materials and Manufacturing Techniques

Our oiirenomi are hand-forged by traditional self-employed blacksmiths with at least 40 years of experience working in their self-owned one-man smithies. They are stubborn gentlemen absolutely dedicated to quality.

These blacksmiths use only Hitachi’s Metal’s Yasuki Shirogami No.1 Steel (aka “White Steel”) for the cutting edge, a plain, exceptionally high-purity, high-quality, high-carbon steel that does not contain significant amounts of chrome, molybdenum, nickel, vanadium, or tungsten, chemicals which are added to nearly all commercial tool steels to make products easier to mass-produce by factory workers, instead of more expensive skilled blacksmiths, with fewer rejects. These alloys add considerably to the cost of the materials, while resulting in a finished product that will not become as sharp as Shirogami steel, will not hold a sharp edge as long, and will be more unpleasant and more time-consuming to sharpen. If you have the sharpening skills, then Shirogami No.1 is a steel you should experience.

The Shirogami high-carbon steel is actually a strip that our blacksmiths forge-laminate to a softer low-carbon steel body and neck. During heat treatment the high-carbon steel layer becomes very hard, but the low-carbon steel body and neck remain relatively soft. In use, this construction protects the hard steel from breaking, which is what would happen if the entire chisel was made of one piece of steel hardened the degree Japanese professional woodworkers demand. It also makes it easier to sharpen the hard cutting edge, a task that would be difficult if the blade was all the same hardness. Please see this this page, this page, and this page to learn more.

Our blacksmiths perform a minimum of 3 heats to each blade while using hammers and spring hammers to forge this special steel. This “hand-forging” process, combined with the special heat-treatment techniques they have perfected over many years, produces a “fine-grained” steel of the sort that has been coveted by professionals for tools and weapons since ancient times. The final hardness is between 65~66 on the Rockwell C hardness scale. Most Western Chisels are softer at 55~60 HRc. This extra hardness makes the blade stay relatively sharper longer, and the fine-grain crystalline structure of the steel ensures each blade will become sharper without sacrificing durability.

These are professional-grade tools made by craftsmen, not factories, and are intended to meet the severe performance expectations for Japan’s most uncompromising woodworkers, unlike the mediocre-quality but attractive-looking “consumer-grade” chisels peddled inside Japan to the amateur market, and outside Japan to the uninformed. How much bacon do you like with your sizzle?

Availability

Our oiirenomi are available individually, or in discounted 10 piece sets (3, 6, 9, 12, 15, 18, 24, 30, 36, 42mm) with Japanese Red Oak or White Oak handles. We have all varieties in-stock ready to deliver.

Our Sukezane brand 42mm oiirenomi with Japanese Red oak Handle. Face View
Our Sukezane brand 42mm oiirenomi with Japanese Red oak Handle. Ura View
Our Sukezane brand oiirenomi 10pc box set with Japanese Red oak Handle. Also available with White Oak handles

YMHOS

© 2019 Stanley Covington All Rights Reserved

Links to Other Posts in this Series

The Varieties of Japanese Chisels Part 1 – The Main Categories

The Varieties of Japanese Chisels Part 3 – The Shinogi Oiirenomi (鎬追入鑿)

The Varieties of Japanese Chisels Part 4 – Kakuuchi Oiirenomi (角打追入鑿)

The Varieties of Japanese Chisels Part 5 – High-Speed Steel Oiirenomi (HSS 追入鑿)

The Varieties of Japanese Chisels Part 6 – The Mortise Chisel (Mukomachi Nomi 向待鑿)

The Varieties of Japanese Chisels Part 7 – The Nihon Mukomachi Nomi (二本向待鑿)

The Varieties of Japanese Chisels Part 8 – The Atsunomi (厚鑿)

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

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

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

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

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

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

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

If you have private 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.” Your information will remain confidential (we’re not evil Google or incompetent facebook).

The Varieties of Japanese Chisels Part 1 – The Main Categories

“Electrical tools are consumables; our tools are part of our bodies. Do not treat tools as just things. It is a mistake to think of tools as just your own. The shape of every tool was not decided recently. Over a long, long time it was decided that this form would be most useful.”

Nishioka Tsunekazu, Temple Carpenter in charge of the Horyuji and Yakshushiji Temple Restorations
Ichimatsu Tsukinomi – Kiyotada

There are many varieties of Japanese chisels, and most people, including Japanese, are confused by the meanings of their names, and their various applications. I am not an historian or archaeologist, but I have been using them for over 40 years both professionally and for the fun of it and like to flatter myself I know a bit about them. Perhaps this and future posts will help de-muddle a little of the confusion.

In this first post in the series I will explain the components of Japanese woodworking chisels, and the two main categories. In later posts I will explain the various types of chisels included in these categories in some detail. But let’s begin with some language matters.

Terminology and Translation

Where a suitable English word is available, I will use them, but for the most part, I will employ the Japanese terms converted from Kanji (Chinese pictogram characters) and Hiragana (phonetic Japanese characters) to the Roman letters used in most English-speaking nations.

The word for “chisel” in Japanese is “nomi” (鑿). The Chinese character used to write this word is complicated, so it is normally converted to the phonetic hiragana letters as “のみ.” You will notice that nomi is part of every chisel’s name, so I will use it too.

Structure and Components of Japanese Chisels

The design of Japanese chisels is a little more complicated than their Western counterparts, but the basic components are generally the same. So let us examine the similarities and differences.

Blade and Neck Construction

42mm Hidarino Ichihiro Oirenomi – Face View

Traditional Japanese chisels have laminated blades with a body, neck and tang made of iron or very low-carbon steel that remains relatively soft during heat treatment. A layer of high-carbon steel is laminated to this iron body at the blade to form the cutting edge. During the quenching process, this layer becomes very hard, typically 62~67 Rc versus the typical hardness of 58~60 Rc found in Western chisels. The two layers are most visible at the bevel. This additional hardness has both advantages and disadvantages, depending on the crystalline structure of the steel after heat-treating and the skill with which the tool is used and maintained.

In the case of hand-forged (teuchi 手打) blades, this lamination is made by forge- welding the two types of metal over several heats using hammer, tongs, and anvil.

European chisels were also fabricated using this technique before the advent of mass-produced inexpensive steel. Unfortunately, this once-universal excellent technique has been all but forgotten outside of Japan.

Materials & Process

The best professional-grade chisels are made of high-quality iron and the purest plain high-carbon steel. These ancient metals are difficult to work, being very sensitive to temperature and thermal shock and tending to warp and crack badly in less than experienced hands. Many alloys and processes have been developed over the last 60 years to make tool production more profitable using unskilled labor, but for simple cutting ability and ease of sharpening, nothing rivals this combination.

The blacksmithing process involves forge-welding the two types of metal to form a laminated blade, then shaping and hand-forging over multiple heats, followed by carbon soaking and annealing, a coating of secret mud sauce after which the blade is heated to just the right temparature and subject to multiple quenches followed by multiple temperings. The process varies from blacksmith to blacksmith with each craftsman using different formulas and procedures. Of course, warpage must be compensated for by shaping a curve in the blade that straightens out during heat treatment. Learning these skills takes years of hands-on training from a young age under the eye of a master, and decades of dedication to quality. It certainly cannot be accomplished in a mass-production situation, much less by Chinese peasants or even CNC robots.

Mass-produced consumer-grade Japanese chisel are made of pre-laminated strip steel manufactured in steel mills by either cold-rolling or hot-rolling a layer of high-carbon steel to a layer of mild-steel. This material, called ” rikizai” (利器材)or ” fukugozai” (複合材)was originally developed for mass-producing inexpensive kitchen knives as a labour-saving material to reduce manufacturing costs.

Blades made from rikizai typically perform adequately for most consumers, but many professionals seek the higher performance of so-called ” fine-grain” steel’s smaller and more uniformly-distributed carbides found in hand-forged, expertly heat-treated blades. Those who develop the skills necessary to discern the difference between such professional-grade and consumer-grade blades, can never be satisfied with the inferior tool.

Hollow-Ground “Ura”

42mm Hidarino Ichihiro Oirenomi – Back View

Japanese chisel blades have a hollow-ground back (the so-called ” flat” on Western chisels) which makes the harder steel easier to sharpen and keep flat. Without this hollow-ground ura feature you would find sharpening a chisel blade of similar hardness time consuming and almost impossible to keep flat over many sharpenings.

Tang and Ferrule

Japanese chisels appears at first glance to be socket chisels, but they are definitely tang chisels. The handle incorporates a steel ferrule shaped like a truncated cone and called the “ kuchigane” (口金) which translates to “mouth metal.”

The Four Components of a Tatakinomi: Blade, Handle, Kuchigane, Crown

This component receives the reaction forces of hammer impacts from the blade’s shoulders converting these thrust forces acting in the handle’s long axis to compression forces acting on the handle’s end thereby preventing splitting and locking the tang tightly into the handle. It is a subtle but clever and effective design that combines the best features of both tang chisels and socket chisels without any of the downsides.

The Crown

The “Keima” Chess Piece

Chisels intended to be struck with a steel hammer have a sturdy steel hoop called a ” katsura” installed at the handle’s end to prevent the wood from splitting. The characters used for this word include 冠, pronounced “kan” or “ kanmuri” meaning “crown” or 桂 meaning Judas Tree or “ knight” (桂馬)as in the chess piece. The word Katsura can also mean “ wig” a term that does not quite work in this case because chisel handles are as bald as I am.

I have the bad habit of anthropomorphising my tools. They hate that, so to avoid giving further offence (they sometimes bite, donchano), I prefer to translate katsura as the more elegant word “crown” instead of the more constrictive word “hoop” or follically-challenged word “wig.”

Just in case you aren’t entirely confused, please note that this same steel hoop is also called a ”sagariwa” (下り輪) which translates to ”drop hoop, ” a term that is accurately descriptive because, over many years of hammer blows, the handle gradually shortens and the hoop “drops,” shifting its position down the handle.

The crown is made of relatively soft but still strong mild steel. In use, it may occasionally be struck by a steel hammer. This choice of material is not based on economics or convenience but on the practical reality that the face of a steel hammer impacting the edge of a hardened steel hoop would get dinged and even deform after enough hits.

But this creates another problem, namely that the crown may eventually become deformed by hammer strikes unless preventative measures are taken. This is not a trivial cosmetic matter because the hoop’s edge may deform to the point it curls back inside itself. Then, if the user continues to beat on the chisel, the hoop will gouge and eventually split the handle.

Damaged Crown and Handle

The best way to avoid this grief is to use a hammer with a flat instead of convex face and to properly setup the chisel when new. For instructions on doing this, please see my earlier post about Setting-up Japanese Chisels.

Another downside to the crown and steel hammer arrangement is that the end of Japanese tatakinoni are far from smooth and can be uncomfortable to use when paring. The solution to this is three-fold. First, setup the crown properly and chamfer and smooth its edges. Second, avoid hitting the crown with hammer so it doesn’t become rough and gnarly. And finally, use a tsukinomi chisel for paring. Life is good.

Handle Materials

Chisel handles can be made of a variety of woods, but strong hardwoods such as oak are commonly fitted to chisels designed to be motivated with hammers.

Chisels not intended to be struck with a hammer can be fitted with more brittle but decorative wooden handles such as ebony or rosewood.

The Two Categories: Tatakinomi and Tsukinomi

Tsukinomi

There are two primary categories of Japanese chisels. I think these same categories apply to other traditions, but in the difference is especially clear-cut in Japan.

The first category is the “tsukinomi “ (突き鑿). Tsuki means “to push,” so tsukinomi refers to push, or paring, chisels. Standard widths range from 1.5mm to 48mm. Handle lengths and materials vary with the type of tsukinomi, the intended purpose, and personal preferences.

30mm Mitsuura Tsukinomi called an “Usunomi” by Sukezane

Tsukinomi are pushed by hand and sometimes by shoulder in the case of the large ootsukinomi, known in the West as “slicks.” Most tsukinomi have relatively longer, more slender and elegant necks. They incorporate the same kuchigane ferrule at the blade end of the handle, but do not have a steel crown hoop reinforcing the opposite end.

Standard Ootsukinomi Set: 24mm and 48mm
Paring the Cheeks of a Beam Splice Using an Ootsukinomi
Paring a Rafter Post Seat Using an Ootsukinomi

By definition these chisels are not intended to ever be struck with a hammer. Even if the handle does not split, their more slender necks will not endure impact forces gracefully. More often than not they are used to clean and pare to final tolerances joints cut using other chisels.

The types of tsukinomi most commonly seen include usunomi paring chisels, shinogi usunomi, kotenomi, and ootsukinomi.

Tatakinomi

The second main category of Japanese chisel is called the “tatakinomi” (叩き鑿)meaning “striking chisel.” This is the style of Japanese chisel best known outside Japan. These chisels are stronger and tougher than tsukinomi and are intended to be struck with a steel hammer.

42mm Atsunomi Ura – Sukemaru (300mm (11.8″) Overall Length)

Wooden mallets are not typically used with Japanese chisels. The logic for this practice is simple: A steel hammer is the smallest, lightest, and most energy-efficient way to motivate a chisel. The physics of this are self-evident. Accordingly, the logic behind the tatakinomi design is that, since it must efficiently remove lots of wood, and a steel hammer is the most efficient way to motivate a chisel, the tatakinomi’s handle must be designed and made strong enough to endure being struck by a steel hammer from sunrise to sunset. A simple calculus.

250 Monme Kosaburo Gennou (938gm, 330z) Black Persimmon Handle

By contrast, the Western tradition of using chisels with inherently fragile handles requiring users to obsessively baby them with relatively soft, energy-wasting, un-aerodynamic, big-ass mallets is illogical and inefficient. But to each his own.

Some people stubbornly insist on using mallets even to strike their Japanese tatakinomi. This reminds me of the country bumpkin that bought a newfangled chainsaw from a hardware store in town to cut firewood only to bring it back the next day complaining it was slower and more work than his old axe and handsaw. The puzzled hardware store owner checked the fuel and spark plug, but found no obvious problems. With a perplexed look he yanked the starter rope. The chainsaw’s motor started right up with a roar and a cloud of smoke. The shocked customer almost jumped out of his overalls in wide-eyed surprise, screeching “ what the hell’s that racket!?!”

According to the Takenaka Carpentry Tools Museum located in Kobe, there are 9 varieties of tatakinomi.

There are many varieties of tatakinomi. The most popular by far is the oiirenomi. We carry several varieties of oiirenomi including mentori, shinogi, kakuuchi, and HSS mentori oiirenomi. Another popular style is the larger heavy-duty atsunomi, preferred by timber framers. And when we can get them, mukomachinomi.

In Part 2 of this series we will describe some of these beginning with the “Mentori Oiirenomi.

YMHOS

Links to Other Posts in this Series

The Varieties of Japanese Chisels Part 2 – The Mentori Oiirenomi (面取追入鑿)

The Varieties of Japanese Chisels Part 3 – The Shinogi Oiirenomi (鎬追入鑿)

The Varieties of Japanese Chisels Part 4 – Kakuuchi Oiirenomi (角打追入鑿)

The Varieties of Japanese Chisels Part 5 – High-Speed Steel Oiirenomi (HSS 追入鑿)

The Varieties of Japanese Chisels Part 6 – The Mortise Chisel (Mukomachi Nomi 向待鑿)

The Varieties of Japanese Chisels Part 7 – The Nihon Mukomachi Nomi (二本向待鑿)

The Varieties of Japanese Chisels Part 8 – The Atsunomi (厚鑿)

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

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

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

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

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

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

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

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