Swedish Steel for LN Aftermarket and Traditional Tapered Blades

[Stanley Covington]

The following are part of my notes from a meeting I had with a Japanese plane blade blacksmith yesterday. The subject was the type of steel to use for a replacement blade and chipbreaker for Lie-Nielson planes, and a tapered blade and chipbreaker for user-made Krenov-style handplanes. I hope you will find it interesting.

The LN after-market blades will have dimensions identical to the stock blades, but will be handforged laminated construction with an RC hardness of 63 - 64. The design of the tapered blades will be based on traditional Sheffield blades prior to the advent of metal or hybrid bodies, but with smaller slots and shorter length to better for the smaller planes promoted by Krenov.

During a meeting on Saturday April 12, 2014 with Mr. T. N., plane blacksmith living and working in Y, Japan the subject of Swedish steel came up.

Mr. N, who was apprenticed to his father and has been making plane blades for over 50 years, uses mostly Hitachi Metal’s Shirogami 2, followed by Aogami 2, as well as Aogami Super. He occasionally uses Swedish Steel and Togo steel.

Mr. N said that Kousuke Iwasaki recommended that he use Swedish Steel for plane blades, and when Mr. Iwasaki passed away, left his store of this metal to him, but Mr. N does not know the material’s designation or manufacturer (i.e. ASSAB K-120).

Mr. N said that Swedish Steel was more difficult to work than Hitachi’s products, and unless one was careful during the forging process, the material was easily ruined, the finished product would turn white, and the blade would not hold an edge. He stressed that the process of hand forging is absolutely essential to the cutting capability of a plane blade.

When I pressed him about what could go went wrong during the hand-forging process to ruin Swedish Steel, he said that one had to be very careful of the temperature, and the number of heats, because if the steel became overheated, or was heated to many times, the nature of the metal would change for the worse, probably due to carbon loss.

All high-carbon steels have this problem, but Hitachi Metal’s products are not nearly as sensitive as Swedish Steel in Mr. N’s experience. He said that, when worked properly, the Swedish Steel he used created a blade superior to any other commercially available steel. He listed the characteristics of a superior blade being: (1) It can be made very sharp; (2) It will stay sharp longer; (3) It is easily sharpened; and (4) It doesn’t chip easily.

Tokyo, Japan April 13, 2014

If you have any thoughts, please let me know, either by reply to this post, or PM.

Stan

[Andrew Hughes]

I would be interested in trying a different steel for my lie nielson planes,I will have to wait as I already bought replacement blades for some of my planes last year.The A2 steel does fall short for my liking and is the reason I divorced myself form their socket chisels. Andrew

[Stanley Covington]

I would be interested in trying a different steel for my lie nielson planes,I will have to wait as I already bought replacement blades for some of my planes last year.The A2 steel does fall short for my liking and is the reason I divorced myself form their socket chisels. Andrew

I understand exactly what you mean.

Stan

[Kees Heiden]

Any idea what Swedish steel is? What is the composition?

[Stanley Covington]

Kees:

I don't know what the composition is because the blacksmith doesn't know the designation, having inherited it.

It may be safe to assume it is ASSAB K-120 (not K-120c powdered metal). But no sure.

Stan

[Kees Heiden]

Thank you Stan. A quick google didn't raise much information. Even ASSAB themsselves don't list this toolsteel.

[Jack Curtis]

I think the thickness of a Japanese plane blade is significant, too; and I don't see how making a thin western style blade suitable for LN planes would provide superior performance. Would this be because of some toughness of the Swedish steel that typical high carbon doesn't have? Have you tried the Tsuenasaburo LN replacement blades?

[Stanley Covington]

Thank you Stan. A quick google didn't raise much information. Even ASSAB themsselves don't list this toolsteel.

I know ASSAB doesn't have any online info about K-120. As I understand it, it was developed specifically for the Japanese market, and is not available elsewhere. But this is was told to me by blacksmiths and retailers, not by ASSAB.

Stan

[Warren Mickley]

What kind of stones does Mr. N use when testing his irons?

[Stanley Covington]

I think the thickness of a Japanese plane blade is significant, too; and I don't see how making a thin western style blade suitable for LN planes would provide superior performance. Would this be because of some toughness of the Swedish steel that typical high carbon doesn't have? Have you tried the Tsuenasaburo LN replacement blades?

Jack:

Yes, I own a 2" Tsunesaburo laminated blade and have used it in my Stanley. I believe it is made from what they call rikizai　利材 over here, which as you know is machine laminated. Mass produced, laser cut, heat treated in ovens, not forged, and no handwork. Worlds better than the stock Stanley blade, but it is not up to the highest level of craftsmanship, and it is priced accordingly

My intention is to make a thicker blade than Tsunesaburo's to fit the LN planes, not the Stanley planes. The I think the stock LN blades are thick enough to dampen vibration and prevent chatter, especially when combined with a softer jigane which should even improve damping significantly (just a guess).

As you know, there are several reasons Japanese plane blades are thick in comparison to Western plane blades. One is to allow for a wider bevel for more stable, easier sharpening. That will not be possible with the standard thickness blade, so irrelevant.

Another reason is to make the blade stiff enough to resist distortion by slight movements of the wooden body. I am sure you are aware of the so called "senbei" or "rice cracker" planes with very thin blades that are so weak that any movement of the body puts them out of commission. Mr. Watanabe, who works under the name Koyoshiya, and I were discussing this very thing yesterday when I asked him to make some dai for me for some relatively thin (certainly not senbei thin) Keisaburo blades. His insight was that thinner blades of the type I brought to him are preferred by tategushi (joiners) and sashimonoshi who work with thinner materials and don't do much heavy duty dimensioning, and so don't stress their plane bodies, and so don't need especially stiff blades, whereas carpenters who do rougher work and take heavier cuts prefer a thicker blade.

So my point is that, within reason, thick is better, but the LN ductile iron body is inherently much much stiffer than a Japanese wooden plane, and the frog supplies tremendous support to the blade, so a blade as thick as one made for a Japanese plane is not an improvement, just extra weight, something the LN planes do not need more of. The prototypes so far have been in several thicknesses and tests have born this theory out.

More importantly, unlike the Tsunesaburo, it will not be mass-produced, but hand forged and heat treated by eyeball (not cooked in an oven or carburizer) by a blacksmith who only does handwork, and has been doing it for over 50 years. That will make a big difference in the blade's performance. I haven't measured Tsunesaburo's blades, but mine will be RC 62-64, the same as the best Japanese planes, so it will be easy to make it very sharp, and stay sharp for many times longer than the standard LN blade.

The plan is to have shallow ura that will not need to be tapped out (ura dashi). I think tapping out is a big problem for guys that, unlike you, are not heavily into Japanese planes. Eventually, the ura will disappear, but then it will be just like a standard LN plane blade. I admit this is a compromise. Any thoughts?

Stan

PS: I didn't respond to your question about Swedish Steel above. I have a couple of planes in Swedish steel (ASAAB K-120), and they perform very well. Are they a helluvalotbetter than Shiro 1? I dunno. Is it tougher? I dunno. It does seem to get a little sharper are little quicker. But people I respect, professionals that use planes all day long, and professionals that make plane blades all day long, say its the beez kneez despite being more difficult to work with, so I must take it seriously.

Not to spread rumors, but there are reliable reports of some problems with Hitachi Metal's QC lately, and some blacksmiths tell me they are buying up old stock of White, Blue and Yellow instead of new product as a result (not that Hitachi makes much tool steel nowadays).

[Stanley Covington]

What kind of stones does Mr. N use when testing his irons?

I don't know. Probably King or Bester, but I can't say for certain. I do know he uses natural stones for the final polish.

Stan

[David Weaver]

What kind of stones does Mr. N use when testing his irons?

Warren, you can assume that it won't sharpen on oilstones if it's 64 hardness, except maybe to be polished.

[David Weaver]

The following are part of my notes from a meeting I had with a Japanese plane blade blacksmith yesterday. The subject was the type of steel to use for a replacement blade and chipbreaker for Lie-Nielson planes, and a tapered blade and chipbreaker for user-made Krenov-style handplanes. I hope you will find it interesting.

The LN after-market blades will have dimensions identical to the stock blades, but will be handforged laminated construction with an RC hardness of 63 - 64. The design of the tapered blades will be based on traditional Sheffield blades prior to the advent of metal or hybrid bodies, but with smaller slots and shorter length to better for the smaller planes promoted by Krenov.

During a meeting on Saturday April 12, 2014 with Mr. T. N., plane blacksmith living and working in Y, Japan the subject of Swedish steel came up.

Mr. N, who was apprenticed to his father and has been making plane blades for over 50 years, uses mostly Hitachi Metal’s Shirogami 2, followed by Aogami 2, as well as Aogami Super. He occasionally uses Swedish Steel and Togo steel.

Mr. N said that Kousuke Iwasaki recommended that he use Swedish Steel for plane blades, and when Mr. Iwasaki passed away, left his store of this metal to him, but Mr. N does not know the material’s designation or manufacturer (i.e. ASSAB K-120).

Mr. N said that Swedish Steel was more difficult to work than Hitachi’s products, and unless one was careful during the forging process, the material was easily ruined, the finished product would turn white, and the blade would not hold an edge. He stressed that the process of hand forging is absolutely essential to the cutting capability of a plane blade.

When I pressed him about what could go went wrong during the hand-forging process to ruin Swedish Steel, he said that one had to be very careful of the temperature, and the number of heats, because if the steel became overheated, or was heated to many times, the nature of the metal would change for the worse, probably due to carbon loss.

All high-carbon steels have this problem, but Hitachi Metal’s products are not nearly as sensitive as Swedish Steel in Mr. N’s experience. He said that, when worked properly, the Swedish Steel he used created a blade superior to any other commercially available steel. He listed the characteristics of a superior blade being: (1) It can be made very sharp; (2) It will stay sharp longer; (3) It is easily sharpened; and (4) It doesn’t chip easily.

Tokyo, Japan April 13, 2014

If you have any thoughts, please let me know, either by reply to this post, or PM.

Stan

Stan, is this takeo nakano?

The tsunesaburo blades are very good, they wear ever so slightly faster than A2, but they wear like carbon steel, so you can continue to use them longer than you can use an A2 iron to the same wear point. Overall, the two will last about the same number of feet if both are good, thus my comment that japanese irons lasting much longer is not really true (it depends on what you compare to, I guess). There may be some difference across various wood hardness - I tested A2 irons on hard maple. A manufacturer of irons sent me an A2 iron to test and it said on the package that it lasted longer than other A2 irons. I thought that was an odd claim given the process was the same as hock and LN use. So I stroke tested irons, and found that LN's A2 iron that I was using (coming off of a shapton 15k) lasted something like 1700 linear feet with a 2 thousandth shaving. For about 2/3rds of that, it gave a suitable surface (because it didn't chip out). The last third, I was just seeing when it would stop cutting, and it was still cutting at 1700 lf, but with so much wear that the surface was bad AND it required a lot of downpressure just to stay in the cut.

At any rate, I haven't found anything short of HSS that will last longer (I've been lucky enough to have planes in super blue, blue cutting (tsunesaburo and yamamoto use it), inukubi (which is more like carbon steel), white #1 and swedish.

Using very fine synthetics (either the micron level synthetics or 1 or 1/2 micron diamonds - I wouldn't use diamonds on a japanese iron, though), the sharpness of the A2 is about the same as carbon steel. Using natural stones or coming up short of the micron or sub micron level, though, the divide is great and it favors carbon steel for sharpness. A year or two ago, mel fulks had mentioned that the reason we have to fiddle with all of our sharpening is because the steel is inferior. I disagreed with him at first, but he has a point. You can sharpen carbon steel on a washita stone and get all you need out of it, but the same isn't necessarily true of A2. But the absolute sharpness off of green chromium oxide powder is about the same (like I said, I don't like to use diamonds on carbon steel).

That said, a japanese iron doesn't actually have to stay sharp longer, all that's needed is for a blogger to say it does, and most of the marks that they work on will never know the difference. They'll just go around parroting what they've read and never put in the several thousand counted strokes that it takes to actually test a claim like that.

I have not had any of the irons I tested hardness tested except for one, the LN iron tested at 61.5 hardness, which had a lot to do with its durability.

I found the tsunesaburo iron to wear about like brent beach's iron did - about as long as A2, though the wear bevel was bigger (but it was very uniform).

http://www3.telus.net/BrentBeach/Sharpen/TSUtest.html

Hock's A2

http://www3.telus.net/BrentBeach/Sharpen/Hock%20A2%20test.html

And the 10 dollar ringer, for good measure. The mujingfang HSS (which you already know is no pleasure to sharpen unless diamonds are used).
http://www3.telus.net/BrentBeach/Sharpen/mftest.html

I guess if I had a choice, a Blue #1 iron would seem the most practical for a plane iron if it could be made with consistent quality and at a reasonable price, no clue if the tsunesaburo iron is blue 1 or blue 2, but it is well done. White #1 would be lovely, but I doubt it could be made cheaply. My swedish iron is an absolute joy to sharpen, as is the togo inukubi iron, but they do not last as long as A2 does. The swedish is Ogata, and the inukubi is nakano (and it is absolutely expertly done, stretched far and thin over very supple kamaji, something that I've read is difficult - stretching inukubi, that is).

[Warren Mickley]

I would not have expected the irons to be designed for workers who can use novaculite. I was curious about Mr. N's stones because I often get the feeling that a lot of the stones that are marketed and discussed were designed for amateurs. I wanted to see what someone with experience and discrimination was using.

[David Weaver]

Warren, this never got answered, and I don't know what most professional woodworkers do, but I have seen suggestions of fairly common synthetic stones by makers of plane irons (e.g, I think kengo usui is described on so yamashita's site as saying that the naniwa snow white is a suitable stone). I also remember Chris Vandiver stating that he'd worked alongside a few professional carpenters who favored the naniwa snow white, which is a decent stone and one in a range that you might consider to be marketed at amateurs.

The sharpening videos online suggest some of the instrument makers, etc, like to sharpen with synthetics and then move to a natural finish stone.

I have seen two attributions of sharpening for the japanese razors, both to iwasakis, though I don't know if one is a jr and one a sr. The first I saw was an account of iwasaki honing a razor to teach someone and he worked the razor through a maruka finish stone (expensive and very fine, though there are a lot of fakes now), but what was shocking was that he used 1 micron diamonds on a soft strop after the maruka stone.

Either the same or another iwasaki described the same process in print, but the final step was graded chromium oxide powder.

I'm interested in whether stan believes the synthetic stones were made to be marketed toward amateurs. I don't believe it's the case with the older ones (the kings and besters), but don't know about the new ones.

One more side comment, the process of matching a natural stone to an iron that is not white steel can be a pain in the butt, esp if someone has gotten hooked on the sub micron synthetic sharpness.

[Stanley Covington]

I don't think the synthetic stones at any time were created specifically for amateur users. I do think that once King stones were successful, and the ceramic and abrasive companies made finely graded grit and fusing media available to anyone commercially, everybody and their dog started baking stones in pizza ovens.

I know you like natural stones, David, but for rough work, the manmade stones are just more consistent and economical, and so the natural stones don't sell. There are stone mines all over Japan, but only a few are still in operation, and those are mostly just finishing stones. You can still buy natural rough and medium stones here in Tokyo at one specialty stone store. I have also been to another retailer in Kyoto not far from my jobsite. He has a great selection, but it is natural finishing stones that sells the best, not his natural rough and medium stones. He sets up at the Kezuroukai every year too.

Nearly everyone that I have ever seen since the 1970's, except for a few professional sharpeners and sword sharpeners, uses manmade stones for everything but the last polish (they don't make them wide enough or long enough or the right shape for swords). I guess this means that synthetic stones were intended to be used by professionals too.

On the other hand, the synthetic finishing stones have become too weird nowadays, and are indeed focusing on amateurs. Stroke for stroke, many are more expensive than high-quality natural stones, and neither the cutting edge created nor the surface of the wood benefit commensurate with the extra cost and time spent sharpening a finish plane blade on some of these stones. I'm sure there are plenty of exceptions, but I have seldom seen a professional tool sharpener use other than manmade stones for rough and medium sharpening, and natural stones for the final polish. Granted, a beautiful finish is the professional sharpener's goal. Apparently amateurs have different goals.

My opinion.

[David Weaver]

Stan, I agree. I have no natural japanese stones more coarse than a tanba aoto, which i find to be unusable, anyway. IF a tool is soft enough, I will run it up through coarse grits on an oilstone (sacrilege, I know, but if a japanese tool is soft enough for novaculite, they get along exceptionally well), but most of my good tools are not soft enough for that and I use synthetic stones on them through a 6000 grit synthetic stone, or an 8000 king and then finish them on a natural finisher.

Decent finishing stones have gotten out of hand with most smaller vendors, and where a good finisher used to be about $200 if bought right, almost nothing of the sort is to be had now unless ordered from a seller who runs an online store called aframestokyo. Everything else is exorbitant to say the least. I've seen a lot of mid grade stones being sold on ebay for $500, stones I really wouldn't want at all because they're too soft. They look like old stock, and they were probably passed over for a reason.

I finally have a good set of natural finishers such that I would really have a difficult time replacing any of them and not thinking that I was just risking getting a worse stone and wasting my money. My favorite of all razor stones that I've ever used is a half worn out (but still flat) piece of stone from ozaki mine. Ozaki stones aren't very flashy or attractive, but they are hard and fine without being cold and uninviting like the finest ozuku stones. I guess ozaki mine is closed, though. Mine came from a barber shop.

I have never tried the iyo stones or any of the other coaser hard natural japanese stones, they have caught on and cost too much, and when it's bad form to take an iron to a grinder, I prefer a synthetic medium stone to get rid of the wear on a plane iron. I am already impatient enough with sharpening. I usually keep a suita stone on my bench when using japanese chisels and keep the chisel in shape throughout the process - 30 seconds here or there every 10 minutes, maybe, rather than letting it dull, but I always let my planes wear significantly before bothering to resharpen them.