Thread: Chisel Hardness Study, the first step.

Yes, that's the article that has the chart in it. I hate to link the whole article if it isn't needed as you have to scroll down some to find that chart.

AEB-L, CPM-3V, YXR-7 (japanese) are all matrix steels - larrin has an article on that, too. They're alloyed, but the grain is really fine. The YXR-7 chisels are sold at very high hardness despite having not-that-much carbon (I think all of the matrix steels are like AEB-L, etc, with lower carbon - which keeps large carbides from forming in them).

I tried to heat treat AEB-L in the open atmosphere and I can get a usable iron, but the hardness spec isn't like Larrin describes. XHP on the other hand is indistinguishable from LV's V11 irons if it's just heated to a high temperature quickly (not good to hold really high temps in the open atmosphere) and quenched, but XHP isn't that widely available and usually not in many thicknesses. The steels larrin likes (the Vanadium-heavy steels) and then others like M42 (lower carbon, but high cobalt) have industrial use and they stay around. XHP doesn't really seem to have any traction outside LV's tools, but I've made some nice kitchen knives with it. It's not quite on par with plain steels as far as edge stability on a knife, but it can be heat treated in a garage and it's not hard to grind (no vanadium).

AEB-L would be a nice plane iron steel, but I think it takes a lot of work and liquid nitrogen to get it to land around 62, whereas something like A2 just sort of ends up there (like O1) without too much effort. So I doubt we'll ever see it.

The knife guys often like a knife a little softer so that it's harder to break or chip out.


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The uddeholm steel - I wonder what it is. The steel I like for chisels is 26c3, which is written about on larrin's site. It's voestalpine (uddeholm) and almost identical to hitachi white 1B (which is not something easy to get if you're not japanese, and 26c3 is available at retail here for somewhere around the same cost as good O1 steel. It's a little harder for an amateur to heat treat, but not that hard and doesn't require anything expensive).

what I'm leading toward is I wouldn't be surprised to see 26c3 in a japanese knife - the properties would be about the same as the high carbon swedish steels or hitachi white. Most of the euro steels aren't sold here due to tariffs and no large market for them, but voestalpine/uddeholm has a mill in the United States so that some of the types (thankfully) don't need to be imported. (just looked - voestalpine is an austrian company and is the parent of bohler/uddeholm) I can't keep up with the locations and mergers/corporate status of all of the companies.

(ASSAB K120 was a popular steel in japanese tools, and probably knives and razors, too - but I see now that either was or has become a company operated by Voestalpine, too).

I have some hitachi white 2, blue 2 and some V-toku japanese steel that's probably not supposed to be sold in the US, but someone on ebay sells it. It's expensive for what it is just like british silver steel rod at retail is really expensive - the hype makes people want it, but voestalpine and hitachi products are probably about the same in quality. The chemistry given for the batches of 26c3 (the retailer that sells it labels the steel so that you can see the actual composition of each batch) is so clean that it's a treat to be able to get it at a reasonble price.

Hitachi white and 26c3 differ only based on small amounts of manganese and chromium differences (neither has any free carbides other than iron - 26c3 is ever so slightly easier to harden due to a small amount of chromium). This isn't very helpful for someone in australia, though!

Originally Posted by D.W.

The uddeholm steel - I wonder what it is. The steel I like for chisels is 26c3, which is written about on larrin's site. It's voestalpine (uddeholm) and almost identical to hitachi white 1B

Yes, the cutting steel in that knife (made by Yukinori Shirataka, Okimitsu the 2nd) is 30yr+ old Uddeholm 26c3 high carbon steel, sometimes called 'Spicy White' by some after Hitachi White #1 (Shirogami #1). The traditional Japanese master knife smiths are known for their use of old UK soft iron (boat chain and anchors being favourites) for their cladding, but unusual for them to use a cutting steel from the West.

As covered by Larrin Thomas in his article on Uddeholm 26c3, getting the heat treat just right to maintain the toughness is an issue with all of these high carbon/low impurity steels, but that is one of the things that the traditional Japanese blade smiths do well.

We can buy Spicy White locally here if anyone is interested in doing so...

26C3 Carbon Steel (Spicy White) 3.6 x 325 x 1000mm - Artisan Supplies

... and also Hitachi White and Blue, when in stock.

Hitachi White Paper Steel San Mai 3.4 x 33 x 344mm - Artisan Supplies

Hitachi Blue Paper Steel San Mai 3.4 x 33 x 344mm - Artisan Supplies

But, stock of almost everything is becoming scarce here lately. The pandemic has had something to do with that and who knows to what extent Putin's outrage in Europe will exacerbate that.

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While on Böhler-Uddeholm, for any woodturners here in Australia reading this thread, the steel used by P&N for their turning tool range (unfortunately now ceased production) was Böhler M2 HSS (called S600). P&N did a good job on heat treating that and they were very good value for the money while available.

Vicmarc briefly ventured into making turning tool here in Australia with PM Vanadis 10 (10V), but that seems to have also ceased now.

Vicmarc were the logical successor to P&N here, but with them out of the game I doubt if we will see another woodturning tool maker here in Australia.

Yes, exactly the same steel that I use (26c3). I wouldn't say it's too hard to heat treat properly, but there are a couple of things you can't do with it. It has nothing in it to inhibit grain growth, so you can't overheat it, and it has nothing in it that would inhibit decarb, so you ...well, don't want to overheat it for long.

What it does have is wonderful ability to adjust to forge heat treatment cycles and then the surplus carbon will yield hardness and very brisk edge taking without being chippy, and if you're hardening and tempering by hand and eye, the results with it are actually better than a commercial furnace.

I devised a method to shrink the grain on it (as much as possible - the carbides are always there, so it doesn't look as fine grained as something like 1095 or O1), which japanese smiths may also do if they don't just heat treat it in a furnace. There's a published book about thermal cycling, but the method in it works to shrink catastrophically large grain. It makes for a usable result, but I adjusted it to get a better result with steels like this.

(this is results from larrin - O1 samples and 26c3 - I made the samples, he tested them).


Screenshot 2021-10-22 145037.jpg

I wrote A2 and XHP on there, but I didn't have those tested - I saw results of 6 ft lbs for XHP but I think it would actually be almost identical to A2 for hardness and toughness at a given hardness - those can be ignored. I was just explaining to someone where they would be vs. my samples.

The reality with 26c3 is that anyone who wanted to foot the bill for a fast quench oil (they are expensive) and who was willing to train their eye could do my thermal cycling and you see where it ends up for hardness and toughness. It sharpens easier than A2 or XHP - it makes a *great* chisel. Even from a dummy like me working out of a garage and experimenting only by snapping steel samples and testing the results actually chiseling and looking at edges. Shade tree science - adjusting based on outcomes and experimenting. Abandoning something that doesn't work (the typical thermal process is referred back to Verhoeven - who knows 500x as much as I do about metallurgy, but the thermal cycling temps he recommends are a little too high).

I haven't made any knives with it yet, but will. I shape it in a forge (hammering), but I don't heat it to forging temperatures and move it around a whole bunch, rather use the heats and shaping in combination with lower temps for thermal cycling.

I think the commercial process gets hardness the same as mine at this tempering temp, and toughness around 8. I think it's extremely uncommon to have an alloy that favors old timey heat treatment by eye. My O1 numbers only match commercial results (but they're far faster and cost about 10 cents per tool to do at home).

Tempering temperature here would was 390F. More entertaining results could be had at lower temperatures (325-350F would give 65/66 hardness numbers), but the chisels wouldn't be as good to use in hardwood. The same is true for japanese chisels - anything around 66 hardness will show problems in hardwoods, but a click or so back (even at 350F) and the white steel chisels are animals in hardwood. I don't know what the incentive is to make undertempered chisels, but maybe there's an advantage in paulownia or other softwoods.

(I actually only got my samples tested due to heckling from a few people as I'd guessed my O1 samples hardness at 61, possibly 62, and 26c3 at 63 or a little more (not based on charts, but based on how they sharpen on natural stones) and got nothing but endless nonsense from people about how you can't tell anything like that and they're probably junk. Larrin thought they'd be junk, too, but tested them anyway. He prefers to suggest that heat treating without a furnace is a bad idea and I'm not sure he was that excited to see the results). To be fair, he showed me two other samples that people had sent him as forged and heat treated by hand and eye, and they were pretty bad. Hardening the way that I did these samples is easy, but it still has to be done right and it requires an attendant who pays attention.

Originally Posted by D.W.

I devised a method to shrink the grain on it (as much as possible - the carbides are always there, so it doesn't look as fine grained as something like 1095 or O1), which japanese smiths may also do if they don't just heat treat it in a furnace. There's a published book about thermal cycling, but the method in it works to shrink catastrophically large grain. It makes for a usable result, but I adjusted it to get a better result with steels like this.

Here is the process that Shirataka used with the 26c3 (+ iron cladding)... see Pgs 5-10.

http://www.330mate.co.jp/PDF/English...s%20making.pdf

The English translation takes a bit of work to decipher, but it is rare to get a detailed description like this of a traditional Japanese blade smithing process.

Off course, the tempering for a knife that will cut food will be different to a chisel that will be struck into wood.

They're a little mum on the heat treatment part, but the actual making of the laminated steel and getting a pretty pattern is artful.

All of that stuff is outside my scope because it's very difficult to get results like I posted above with the characteristics of the final steel if the knife is forged heavily - there will be some carbon loss and then some kind of thermal cycling needs to be one to refine grain if really chasing fine grain. Not sure if the smiths do that or if it doesn't matter (slightly enlarged grain isn't the worst thing in the world).

There's also one advantage shown here that I've noticed when making knives out of prelaminated steel (prelam v-toku and white 2 can be found on ebay here with some regularity). You can harden a knife fully, and tap the cladding layers and straighten it. If you do that with a solid fully hardened bar of 26c3 (as in, no outside softer layers), it will break like glass. There are two possible solutions to deal with that, at least practical ones:
1) leave the spine of the knife partially or unhardened (there are japanese makers who do that, but not many - apparently that's also a traditional method of making japanese knives, but I think the aesthetic that sells in the west is cladding, especially patterned cladding)
2) partially quench and then finish the tail end of the quench between aluminum plates and then introduce to cold finish temperature


Most of the higher end japanese knives are about the same temper as the chisels and planes, though I've only had four japanese knives so I can't really estimate how they're all tempered. Their stated hardness is about the same (64/65). Knives are a little more forgiving than wood chisels to temper a little too soft or a little too hard (not a lot, maybe, but a little) as the bevel can be made thin and then some edge damage isn't a huge deal in use. The CATRA test that larrin uses actually wouldn't have much of a problem with an untempered tool because it doesn't test toughness.

A lot of the lower end knives are closer to the 61/62 range (which is still a great knife), but I don't know why that is as they're often blue 1 or blue 2. I guess they're made quickly. "low end" still means a knife in the $100 range, so not really low end.

The part that's not published or described well is the thermal management, though, and I've published it in video and will post it on the web (am in the process of it) in text form. As in, you can literally buy rolled material (which is already essentially forged, just with carbides elongated), modify the carbides to little balls with thermal cycling, and match the results you'd get in japanese knives or tools (the best of them).

There's actually a bit of a semi-religious fervor about heat treating anything with more than about 0.8% carbon in the open atmosphere. I sent larrin samples to be tested to quiet people who hassled me constantly every time I talked about hardening. Larrin also assumed I'd send him terrible samples. I figured that publication of my cycle might be useful for people who would like to make a few things but not buy a $2400 HT furnace (that turns out to produce worse results with 26c3).

I kind of figured it wrong, it appears - Larrin didn't (still doesn't) have much experience with forge heat treatment and recommends against it. He'd started with a video series about HT in a forge and suggested it's not going to lead to reasonable results, and I offered to help him advise otherwise an give him the cycle. He was a little dismissive about it, but I get the whole knife market thing - it's easier to trade information on heat schedules, have someone buy a furnance and apply the schedule. My supplier of choice also sent me a nonsensical response when I offered to help them publish information for the beginner/intermediate users re: O1, 1095 and 26c3. This remains the advice on their site - it's not really correct - heat treating O1 to match furnace spec is easy. It's one of the easiest steels to heat treat because it fully hardens easily and the grain can be shrunk easily. I don't anticipate really ever making a dent even though I could teach anyone to do the thermal cycling that I do in 15 minutes, and they could be good at it within a week having spent about $3 in propane to learn:

"New Knifemakers - I’ve heard many beginning knifemakers say O1 and 1095 are the best steel for beginning knifemakers. When I ask where they learned this information, they almost always say YouTube. Do not believe anyone on YouTube who says 1095 and/or O1 are the best beginner steels. They are wrong. If they are wrong about steel, what other erroneous information are they sharing? In my opinion, the best steel alloys for beginners are 1084, 15N20, 5160, 80CrV2 or 8670. All these steels are much easier to heat treat than 1095 and O1.I do not recommend O1 for beginning knifemakers unless you have a heat treating oven or will send your blades out for heat treating. If you heat treat O1 yourself without have the proper equipment and the knife does not perform well, do not complain. You have been warned to use a different steel.
Heat Treating Misinformation - There is a tremendous amount of bad information regarding heat treating O1. Many people think the alloy can be properly heat treated in a coal and/or propane forge. This information is incorrect. To make a knife from O1 that performs to the maximum potential, you must read and follow the heat treating instruction on the data sheets.
We do not disclose the mill where this alloy is made. The mill is located in Europe and has very tight tolerances for alloys they produce."

My draw to this is that it's accessible - as in, these simpler steels (just mostly iron carbides and nothing else) can be done at a really high level by anyone - as good as anything in plain steel that's ever been made with nothing more than a paint can and a couple of plumber's torch (well, you do have to spend $80 on proper quench oil) and a toaster oven. I think when something is accessible, it starts to lose its draw and attractiveness. But it's been my off and on fascination over the last year and a half to really nail doing this by eye (not the skill itself, but finding out what makes a difference), and it was a little annoying before I had test results to deal with people who sit in a chair and never try anything talking about what they've read. The dismissiveness after the fact gives me the sense that this is sort of a semi-religious thing. Like if I made a bunch of 64 hardness chisels and showed that they outperform everything made commercially (especially the eyebleeding price stuff like blue spruce that's got far more in polish than it does in substance), I guess it would be more romantic. Especially if I talked about secret thermal cycling, showed the toughness results and showed comparative grain size pictures (before and after thermal cycling).

that fact that a lot of japanese older smiths still do hardening and tempering in open air suggests that it's not that inaccessible, either -they have to be able to do it with aged eyes and hands (and I can confirm the value is in experimenting, then the method is easy).

David, I hesitate to comment on any of your post as I have little experience to bring to it.

Originally Posted by D.W.

There are two possible solutions...
1) leave the spine of the knife partially or unhardened (there are japanese makers who do that, but not many - apparently that's also a traditional method of making japanese knives
2) partially quench and then finish the tail end of the quench between aluminum plates and then introduce to cold finish temperature

On differential hardening... the favoured method by the traditional Japanese blade smiths was/is to coat the exposed hard metal (ha-gane) with clay and leaving the cutting edge exposed to take the hardest quench.

The deba knife only has soft cladding on one side, so the hagane side benefits from differential hardening. The boundary line between the steel coated in clay and the cutting edge is called the hamon. Evidently 26c3 gives a pronounced hamon.


David, should you ever make some kitchen knives from Spicy White I would be interested in buying one from you. Perhaps one with a hamon line...

I think the reason they hedge so much is so jimmy bbq grill can't claim they sent him the wrong material when his results come out horrible... It is one of the harder learning experiences I had to to swallow.. Just because it can be done does not mean you can do it, especially if you want perfection without a massive investment in materials, equipment, and training. Skill takes time and practice.

Anyway, I tested unicorned edges on two more Buck chisels. Both 1". The edge on one holds up poorly. The other went a long time, like the 3/4" Buck. Which means the edge on one goes 8x or 10x longer than the other one... The one that fails does so by chipping.

What bothers me is that I can't really seem to stop the chisels that chip, from chipping. Paradoxically, a higher edge angle seems to result in failure sooner than later, which probably means plywood's nasty included abrasive (grit, floor sweepings, etc) is damaging the edge, and the higher forces required to push the fatter bevel simply overcomes the edge strength faster when it hits grit. Except if I unicorn the edge less - it fails faster too.

It's got me wondering what they got right on the "good" ones... I'm assuming it was the same steel that went through the same factory process. Were they tempered little softer? Did they get tempered longer? Better grain structure? Carbon more completely dissolved into solution? Or did they just overheat it during heat treatment.

I'm sort of tempted to pull the blade on the poorer performer and draw its temper progressively to see what happens. But then again, I'm tempted to jettison the dud and move on.

The devil of it is that they do so much better than everything else I own... It's like opposite day and the world is upside down.

I suppose the one upside is... I'm sort of lucky that the confluence of my crazy trial and their process happens with some cheap chisels and not the most expensive things on the market. I might not be so happy if the only thing that ran well was Damascus Tasai presentation chisels that run a grand a pop...

Originally Posted by truckjohn

I suppose the one upside is... I'm sort of lucky that the confluence of my crazy trial and their process happens with some cheap chisels and not the most expensive things on the market. I might not be so happy if the only thing that ran well was Damascus Tasai presentation chisels that run a grand a pop...

Price and reputation aren't always an indication of performance.

That was my Tasai chisel (purchased many years ago before the prices went ballistic) that was added to Rob Streepers test. It performed OK but at today's prices not that many times better that some of other chisels that he tested.

I would send it on to you to have a play with if we could get it back from Rob, but he doesn't seem to be active on the forum anymore or responding to messages.

Originally Posted by NeilS

Price and reputation aren't always an indication of performance.

That was my Tasai chisel (purchased many years ago before the prices went ballistic) that was added to Rob Streepers test. It performed OK but at today's prices not that many times better that some of other chisels that he tested.

I would send it on to you to have a play with if we could get it back from Rob, but he doesn't seem to be active on the forum anymore or responding to messages.

To be honest, I'm not sure it would do well in my hands. For whatever reason, I seem to have consistently pushed the failure mode of my chisels to either chipping edges or wearing ok. That's a mystery, as before when I was fooling with microbevels - I got a mixture of chipping and rolling that reduced as edge angle increased. Granted, the "Average" unicorned chisel is going twice as long before I ding it's edge...

There's a possibility I'm inducing microcracks in my process, which then let go in use. I saw this in a Pfeil chisel. It picked up a chip, I buffed it back up without rehoning. Ten minutes later, the whole edge fell off. I had consistent trouble with these wanting to roll in my microbevel trials.

The thing is, when the books talk about "Edge retention," they're generally talking about pure abrasive wear with no chipping or rolling. I have the distinct impression that until I get a better handle on premature edge failure, I'll never actually get an accurate picture of "Edge retention."

Big picture wise, maybe that doesn't really matter that much, so long as my tests point me toward processes and tools that actually work in my hands.

Originally Posted by NeilS

David, I hesitate to comment on any of your post as I have little experience to bring to it.



On differential hardening... the favoured method by the traditional Japanese blade smiths was/is to coat the exposed hard metal (ha-gane) with clay and leaving the cutting edge exposed to take the hardest quench.

The deba knife only has soft cladding on one side, so the hagane side benefits from differential hardening. The boundary line between the steel coated in clay and the cutting edge is called the hamon. Evidently 26c3 gives a pronounced hamon.


David, should you ever make some kitchen knives from Spicy White I would be interested in buying one from you. Perhaps one with a hamon line...

if I ever do make a few, I'll send you one. They won't be expensive. Yes on the white steel being easy to create a hamon with - actually it could probably be done without clay, but I guess clay lets you do it more accurately. The thing that makes 26c3 (and 1095, etc, white 2, white 1, etc) good for a hamon is that it needs a really fast transition to fully harden. It needs to go either right into a special oil or water (water is a no-no unless the blade is laminated, though there's still a risk of cracking with that, and I guess even with fast quench oil, there's a risk of cracking).

So if you sort of get part of a blade into a quench and then either etch or abrade the steel around the dip line, things will transition from bright polish to dull (based on varying hardness). I suppose without clay, the line would be smudgy.

I mentioned something about larrin above, I think - he got back to me on other samples tempered at 400F - 1095 at 63.1 hardness (it attains surprisingly high hardness after temper, which means it's probably about C67 before temper.), but relatively poor toughness. However, after first sulking about the results, I noticed the toughness is about the same as larrin's furnace chart (so I basically hit the target but didn't look beforehand to see that 1095 doesn't really have much toughness).

The 1084, though, I bit it on (which is fine, it's the least likely steel that I'd use) - no clue why - good hardness, poor toughness (1084 should have good toughness). It may have just been a bit undertempered, but even so, poor for that. My first failure so to speak, but with something I've never really snapped and looked at.

I continue to be puzzled by the suggestion that it's easy to harden and O1 isn't.

And, no problem on all of the temperature talk - temp control is very important for someone hardening by eye, but not like thermocouple - just knowing what it looks like when steel is too hot to be sitting at a given color in the open atmosphere (too long, and the grain grows. 1095, white steel, 26c3, etc, don't have much in them to prevent grain growth - or really anything - and if they allowed to get too hot and stay hot for any duration, the grain grows. A small amount of vanadium prevents this to some extent. People hate the term "chrome vanadium", but small amounts of it that don't roam free as carbides, and steel is probably improved a little. I've learned that few people really want to harden anything, even when they say they want to. And in reality, just heating good O1 steel to nonmagnetic, and then some hotter makes a good quality blade.

Larrin seemed to be somewhat pleased that this round of samples weren't quite so good, at least not like the ones charted earlier

Originally Posted by truckjohn

To be honest, I'm not sure it would do well in my hands. For whatever reason, I seem to have consistently pushed the failure mode of my chisels to either chipping edges or wearing ok. That's a mystery, as before when I was fooling with microbevels - I got a mixture of chipping and rolling that reduced as edge angle increased. Granted, the "Average" unicorned chisel is going twice as long before I ding it's edge...

There's a possibility I'm inducing microcracks in my process, which then let go in use. I saw this in a Pfeil chisel. It picked up a chip, I buffed it back up without rehoning. Ten minutes later, the whole edge fell off. I had consistent trouble with these wanting to roll in my microbevel trials.

The thing is, when the books talk about "Edge retention," they're generally talking about pure abrasive wear with no chipping or rolling. I have the distinct impression that until I get a better handle on premature edge failure, I'll never actually get an accurate picture of "Edge retention."

Big picture wise, maybe that doesn't really matter that much, so long as my tests point me toward processes and tools that actually work in my hands.

I couldn't find any legitimate use of chisels where edge retention matters in the sense that knives and charts show (usually abrasive wear tests, or some novel test that might do abrasive and adhesive wear).

You could set up a paring test with chisels that would test abrasive wear, but it would have to do something that we wouldn't normally do woodworking (like if you could create some setup that takes 2 hundredths of end grain off of a board over and over and over, it would be more like planing.

Planing, if a plane iron holds together at all, will often mirror a catra machine but it's also hard to come up with a realistic plane test. I sort of did a few years ago and planed about 40,000 feet of wood only to find out that the second place iron (V11) doesn't really maintain its wear interval over something like O1 or water hardening steel unless you can find a very idealistic test for it (my test was literally that - just sort of go to sleep on my feet and plane thousandths - tens of thousands of feet of beech edges) and then take pictures of edges and weigh the shavings to make sure the amount of work done was fair. None of the irons in my tests chipped (which I thought I'd see), and then I went back to regular work and was constantly chasing chips out of the V11 iron that I had because I was using it for heavier work than just smoothing continuous wood.

I made a bunch of irons at the time out of XHP for smoothers and especially for my metal jointer - same thing (that's my iron and not LV's), I found the "fine edge" less stable and more willing to release little notches of steel.

But in the idealized test, V11 dominated - doubling O1, and was very smooth. I wonder how many people have a situation where planing is like that, though - continuous shavings from start to finish, no dirt, and no interruptions like saw marks, etc.

As you're finding with chisels, when you do encounter something that damages plane iron edges, the composition of the iron may not matter that much - it's tiny as a factor in comparison to modifying the geometry of the edge. Even a fairly mediocre iron can be set up to plane through silica granules in wood on long grain, but the best iron can't handle it at all with something like a 30-35 degree apex. The user and their ability to accommodate the tool correction is far more important. If you have, say, V11 with a 35 degree microbevel and a cheap $10 amazon iron that's modified to deal with the silica, the latter will plane four or five times as long and leave a surface without lines, and then sharpen quickly. The silica dings from cocobolo go about 4 thousandths of an inch deep in some cases and it takes a long time to hone that off. A regular cycle of pretty significant honing on an iron is - from what I can tell - only about a thousandth of an inch in edge length.

Ok, so that sounds exactly like what's happening. The "good quality" stuff hits the grit and knocks off a chip. The Buck and Mintcraft just seem to abrade however much one grain of grit would abrade the steel under whatever compressive pressure the cut creates.

In theory, this should be something that's controlled by correctly processing the steel, and then getting the edge prep right.

Watching videos of chisel manufacturing... The whole heat treatment process is a once and done proposition. It's forged, then normalized (maybe, maybe not..), hardened, tempered once, then ground.

From your discussions on heat treating routines, I see a lot more steps and touches than most manufacturing operations would see as favorable. All those touches cost money, require space and machines, create "in process" inventory, as well as providing more opportunities for failure/problems.

Could they be done? Sure, but it would take a "workshop" where skilled craftsmen work, rather than a factory where unskilled operators tend machines.

More strangeness in my testing... So I tried some chopping to see how the results compared to my paring... Weird... well, maybe not too weird.

The cheap Chinese Bucks that go forever paring at 25 degrees and some buffing simply roll edges in Douglas fir even past 35-degrees + buffing. This Douglas fir is nasty stuff... The hard rings are super hard, but it won't tolerate tools being even a little dull like cherry/walnut/maple/mahogany will.

Harder chisels really do astronomically better chopping, but I need to hone them up to 30-35 degrees before buffing to get them settled in.

Now I see why DW recommends the coarser Yellow compound.... With my white compound, it cuts more slowly, and so requires steeper initial honing angles and a lot more buffing. I think a more aggressive compound would let me start with a lower initial angle and still skirt edge damage. One more thing to try... :b