San Mai layered construction: Why not more?

Exactly :thumbsup:

San-mai was created to make high carbon steel stretch as far as it could in making swords. It was largely a method to make a les breakable sword.
In battle - a bent sword can be straightened under your foot ... and chipped sword will still cut ... a broken sword means a quick death.

There was a lot more than just san-mai. Various methods of kitae were used in making a high quality sword with only a high carbon edge.
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Stacy E. Apelt - Bladesmith said:
Exactly :thumbsup:

San-mai was created to make high carbon steel stretch as far as it could in making swords. It was largely a method to make a les breakable sword.
In battle - a bent sword can be straightened under your foot ... and chipped sword will still cut ... a broken sword means a quick death.

There was a lot more than just san-mai. Various methods of kitae were used in making a high quality sword with only a high carbon edge.
202209181321091657.jpg


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I’ve been reading “The Art of Japanese Sword Polishing”. It’s amazing how much they understood about metallurgy, hardness and edge retention so long ago. San Mai was an ingenious solution but Ashi lines and their clay/heat treating processes were brilliant. Makes you wonder what knowledge has been lost over the centuries.
 
Takaiwa's book is what I would call the master class in togi. I learned most all I know from it. It is a good guide for creating a hybrid polish technique.

I will caution any new smith that what he does effortlessly took him 50 years to master. Don't expect to get his results in a polish or the hamon techniques he shows in yaki-ire for a long time.
 
Stacy E. Apelt - Bladesmith said:
Takaiwa's book is what I would call the master class in togi. I learned most all I know from it. It is a good guide for creating a hybrid polish technique.

I will caution any new smith that what he does effortlessly took him 50 years to master. Don't expect to get his results in a polish or the hamon techniques he shows in yaki-ire for a long time.
Click to expand...
Not to derail the discussion but it kind of fits with the aesthetic side of the issue, I’m curious as to your thoughts on polishing in the same spirit as the San Mai topic. It seems that with modern equipment and abrasives we’re starting closer to the end of the book. He talks about polishers being careful not to change the shape/profile of a sword. What do you think the book/technique would look like if you started at a 400-600 belt finish? Also, is there any literature on San Mai and other techniques as the sword polishing book?
 
I have a strong suspicion that the now traditional, then cutting edge, method of making steel in Japan during the Period of Warring States had something to do with the difficulty of producing quality blade steel in quantity using that traditional technique. In the same approximate time period, quantities of quality sword steel were being produced in South India and distributed across the Middle East as finished blades and unforged billets, known in the West to as "Watered Steel, Damascus or Wootz."


My perception is that much of the materials put into the crucible comes out as lower quality steel, with smaller amounts being high quality carbon steel suitable for forging into a blade that can be hardened. A good part of this is probably the nature of the raw materials at hand. I may be mentally squinting . . .I could easily have gotten that wrong. Whatever the true case. the Japanese swordsmiths laminated together steels with different properties to get a superior Produce. Some laminations were simple while others were complex. Regardless, their craft is amazing and the surviving examples often approach art./

en.wikipedia.org

Japanese swordsmithing - Wikipedia

en.wikipedia.org en.wikipedia.org

My supposition is that some form of lamination, using carefully selected modern steel formulations could produce a blade with superior performance properties compared with quality blades forged today. Cost of production and/or technical difficulty can't be obstacles to this concept: The technique of laminating different steels (not pattern welding) is already being done on both a custom and production basis, but its use seems to be a marketing thing rather than a performance-oriented thing.

Doing so could/might put a point on the chart that is located diagonally "up" and to the "right" of Magnicut.
 

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The polishing in the book is aimed at exposing the hada (pattern of grain) in the steel as well as making the hamon as distinctive as possible. The secondary purpose is to shape and sharpen the blade. Traditional togi done as in Takaiwa's book is age old and done by hand start to finish. It is deeply rooted in tradition and is almost a religious exercise. A togishi at Takaiwa's level it is an artist.

The main issue/difference between traditional togi and modern bladesmithing techniques in polishing is the materials more than the equipment. Western bladesmiths generally work in modern alloyed steels made in a factory and modern damascus. Togi is designed for finishing traditionally folded tamahagane and other forged and folded blades. The other issue is we are making swords and knives. Takaiwa is making and restoring nihonto blades. It has to be done his way or it will be wrong. No matter how nice I make a sword, it is just a SSO to a Nihonto collector. My nicest sword may be worth a couple thousand dollars. A good nihonto may run ten times that. An ancient papered nihonto can run $100,000. This is why the owners of these swords pay $100-150 an inch to polish them.

Shitaji togi (rough polish) with stones and files is pretty much the same as we shape a blade using belt grinders and power tools. It forms the basic bevels and shapes.
I don't think it would matter much which way the blade was shaped in shitaji togi.

Shiage togi is to polish the blade and bring out the features in the steel formed by the forging and and yaki-ire. Primarily, it develops the hada and hamon. It is different than a belt and buffer finish. If you used the power equipment we use to finish blades in our usual way it would not get the same results. Power grinders and buffers would blend out much of the fine details. Much of the final result is in "reading the steel". This is a slowly learned ability to understand what the steel in the blade went through in its formation and how various oxides and abrasives will affect the look.

The modern blend of the two is called a hybrid polish. It starts as a standard belt finish and moves to hand sanding and hand polishing with various grits. It leaves out the hazuya/jizuya finger stones and other tedious techniques. It does require hand polishing of the hamon areas, but with a far lesser degree of supplies. Hybrid polish rarely uses stones for finishing. If you just sanded to 4000 grit and buffed the blade it would look good, but sanding to 2000 grit, using etchants, and then hand finishing with various oxides along the edge to show the hamon gets a more stunning effect.

In most cases, a modern polish and sharpening is sufficient for our blades. On a blade quenched to form a hamon, a bit more work and care is needed, but we are usually satisfied with a nice visible hamon. On a nihonto blade, the polish we find acceptable would be considered a total failure and could even make the blade worthless. This is why folks like Nihonto Ed always say that no one but a registered togish should polish a true nihonto blade. If you don't do it right you ruin the blade. Any blade that is suspected to be hand forged and of Japanese origin should be checked by an expert, preferably the NBTHK, before doing any polishing.

Final comment:
I am amazed that togishi like Takaiwa have any fingerprints or even fingertips. They polish the hamon and ha with tiny paper backed chips of stone on a razor sharp blade laying on their lap at blurring speed while talking to someone. I cut myself sometimes just wiping a blade off.
 
So laminate AEBL side panels (toughness) to S90V core for edge retention. AEB-l Austentizing temp is mid 1900's, S90V is 2000-2100 or so. So when you put the steels together, you are getting sub optimal on the AEB-L steel, hotter temps means more grain growth, there goes your toughness! The steels have to have a heat treat that matches up well.

Or do 410 stainless side panels with S90V core. Basically it allows less S90V used, but since S90V is the core, you aren't gaining more toughness through the side panels really since the core itself can be more brittle, so the edge chips out easily, or more likely to break with tougher use. Grinding may be easier since it's less grinding on the S90V, sharpening is still sharpening the S90V core, but a thinner portion of it. So unless you are grinding and sharpening way up the blade like a kitchen knife, you aren't really gaining much and what you are gaining is ease of sharpening, but if you grind the blade thinner at the edge to begin with and with high edge retention, you will have to thin it out less often because you are sharpening it less often. Performance wise/toughness wise, you aren't gaining all that much.

So laminating modern steels is more of a cost perspective (less of the expensive steel) and ease of maintenance down the road for steels that don't have as high wear resistance. But the laminating takes time and money, so it's often a losing battle.

In modern steels, you pick the steel itself that has the balance of properties. If I want a tough stainless knife for heavy use, AEB-L/NitroV/14C28N gets the nod. A little less toughness, better edge retention, CPM 154. Balance between tough and edge retention, Magnacut. Higher edge retention, S90V or CPM20CV, etc. The steels themselves balance out in various areas so you pick the steel that gives you the blend of properties you want instead of having to laminate steel.
 
In response to your post before mine:
What you say is technically true, but not practical.. If you stacked 1070 and 1150 then folded them to a million layers, you would get something similar to tamahagane. People do that for fun. However, it would not be tamahagane.

Using a high quality mono-steel would make a better blade anyway. Just like there is no advantage in damascus over a mono-steel, there is no advantage in a layered and folded multi-steel blade. The edge is what cuts. It does not matter if the rest of the blade is different, but the best plan is to have the entire blade the same metal and HT it accordingly. Any other reason is asthetics.
 
My current carry blade is 10V Core/154CM clad san mai. It does address the issues of corrosion, to a degree, but really, it's just for the look.
 
Also consider labour costs. Labour used to be really cheap, materials were expensive, so a slower process that saved material was useful
Now that has reversed, even a machine operator is far more expensive than the raw materials that go into knives. Let alone an expert bladesmith (a ~1m bar of magnacut at retail prices is like 10 hours minimum wage here)
A mono-steel stamped/waterjet knife with a full tang can be done really quickly with modern equipment, especially in a factory context. A san mai hidden tang is more work, so more money

And Japan are big on tradition, which is partly why san mai has persisted there. You can still find a lot of vg10 Japanese knives though
 
^interesting point re; labour costs
 
How can one patent the term "san mai"?! It is Japanese for "three layers." I'm going to go out and fire up my grill and make a double cheeseburger: meat cheese meat, and call it a san mai burger.
 
There have been several long threads about Cold Steel and san-mai.
First - They did not patent it. The registered a trademark for SAN MAI and SAN MAI III.
Second - the words san-mai, sanmai, san mai are all fine to use in advertising and marketing your knves.
Last - You have to look in the disclaimer in the initial 1988 trademark application to see that they know it is indefensible except exactly as they use it in their all caps trademark spelling . Here are the secret words,
"NO CLAIM IS MADE TO THE EXCLUSIVE RIGHT TO USE "SAN MAI" APART FROM THE MARK AS SHOWN"
They left that off the 2008 renewal applications, but it still stands.

Here are the trademark papers:

Word Mark SAN MAI
Translations The foreign wording in the mark translates into English as "three layer".
Goods and Services IC 008. US 023 028 044. G & S: Folding knives; Hunting knives; Sport knives. FIRST USE: 19860722. FIRST USE IN COMMERCE: 19860722
Mark Drawing Code (3) DESIGN PLUS WORDS, LETTERS, AND/OR NUMBERS
Design Search Code 26.17.02 - Bands, wavy; Bars, wavy; Lines, wavy; Wavy line(s), band(s) or bar(s)
26.17.05 - Bands, horizontal; Bars, horizontal; Horizontal line(s), band(s) or bar(s); Lines, horizontal
Trademark Search Facility Classification Code INAN Inanimate objects such as lighting,clouds,footprints,atomic configurations,snowflakes,rainbows,flames
NOTATION-SYMBOLS Notation Symbols such as Non-Latin characters,punctuation and mathematical signs,zodiac signs,prescription marks
NUM-3 The number 3 or the word Three
SHAPES-BAR-BANDS Designs with bar, bands or lines
SHAPES-MISC Miscellaneous shaped designs
Serial Number 77455749
Filing Date April 23, 2008
Current Basis 1A
Original Filing Basis 1A
Published for Opposition September 16, 2008
Registration Number 3540202
Registration Date December 2, 2008
Owner (REGISTRANT) Cold Steel, Inc. CORPORATION CALIFORNIA 6060 Nicolle Street Ventura CALIFORNIA 93003
Attorney of Record Glenn J. Dickinson
Prior Registrations 1471971
Description of Mark Color is not claimed as a feature of the mark. The mark consists of the words "SAN MAI" followed by three horizontal wavy lines.
Type of Mark TRADEMARK
Register PRINCIPAL-2(F)
Affidavit Text SECT 15. SECT 8 (6-YR).
Live/Dead Indicator LIVE

Word Mark SAN MAI III
Translations The non-Latin character(s) in the mark transliterate into 3, and this means the number 3 in English. The foreign wording in the mark translates into English as "three layer".
Goods and Services IC 008. US 023 028 044. G & S: Folding knives; Hunting knives; Sport knives. FIRST USE: 19860722. FIRST USE IN COMMERCE: 19860722
Standard Characters Claimed
Mark Drawing Code (4) STANDARD CHARACTER MARK
Trademark Search Facility Classification Code NUM-3 The number 3 or the word Three
Serial Number 77455291
Filing Date April 22, 2008
Current Basis 1A
Original Filing Basis 1A
Published for Opposition September 16, 2008
Registration Number 3540187
Registration Date December 2, 2008
Owner (REGISTRANT) Cold Steel, Inc. CORPORATION CALIFORNIA 6060 Nicolle Street Ventura CALIFORNIA 93003
Attorney of Record Glenn J. Dickinson
Prior Registrations 1471971
Type of Mark TRADEMARK
Register PRINCIPAL-2(F)
Affidavit Text SECT 15. SECT 8 (6-YR).
Live/Dead Indicator LIVE

Word Mark SAN MAI
Translations THE ENGLISH TRANSLATION OF THE WORD "SAN MAI" IN THE MARK IS "THREE PIECE".
Goods and Services IC 008. US 023. G & S: SPORTING KNIVES. FIRST USE: 19860722. FIRST USE IN COMMERCE: 19860722
Mark Drawing Code (3) DESIGN PLUS WORDS, LETTERS, AND/OR NUMBERS
Design Search Code 26.17.09 - Bands, curved; Bars, curved; Curved line(s), band(s) or bar(s); Lines, curved
Serial Number 73644095
Filing Date February 11, 1987
Current Basis 1A
Original Filing Basis 1A
Published for Opposition October 20, 1987
Registration Number 1471971
Registration Date January 12, 1988
Owner (REGISTRANT) COLD STEEL INC. CORPORATION CALIFORNIA 3036-A Seaborg Avenue VENTURA CALIFORNIA 93003
Attorney of Record Glenn J. Dickinson
Disclaimer NO CLAIM IS MADE TO THE EXCLUSIVE RIGHT TO USE "SAN MAI" APART FROM THE MARK AS SHOWN
Type of Mark TRADEMARK
Register PRINCIPAL
Affidavit Text SECT 15. SECT 8 (6-YR). SECTION 8(10-YR) 20080102.
Renewal 1ST RENEWAL 20080102
Live/Dead Indicator LIVE
 
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