Thread: One more observation about wood quality when planing - or surface quality

One more picture - the blue steel japanese iron. When I tested irons, I was shocked in that I expected to find this to be the "best" of all of the irons. I also didn't have a good grasp on just how much alloy influences wear resistance, but was confident in my findings because of my ability to plane consistently and then how similar each test iteration was.

Confidence can be offputting and people who didn't like the study results wanted to find something wrong with it. One of them later told me that Kees Heiden made a honing machine and it honed V11 half as fast as O1, which is a good indicator of ideal plane iron life, and he didn't like Kees' results because V11 is all chromium carbide. If you talk to knife fanatics, most of them love vanadium carbides and I think a knife metallurgist had helped this person pick 3V for plane blades and chisels. The same person is a chemist, though, I described the test procedure and he relented on trying to figure out why both tests agreed (v11 planed already planed wood twice as long as O1 - I thanked him for not telling me ahead of time and in the test itself was almost in disbelief. Almost as much as I was disappointed later when V11 and XHP went back in more wide open planing work to being what I'd experienced before. That (shooting and planing wood from rough) wasn't in agreement with the test.


We understand all of that now, and Larrin thomas released catra test results which matched my planing intervals aside from his O1 sample (which he suggested to me offline may have had problems - the results weren't terrible, but O1 outlasts 1095 and 1084, and things of the like - his catra sample was a little off).

Getting back to the blue steel iron - I thought fineness of the steel and higher hardness could really contribute to a better experience because when you're actually working steel, something like an ideal O1 iron is about as practically productive as you'll get. You wear it until it loses clearance, sharpen it quickly, and keep going. thus, the 65 hardness blue steel iron would almost *have* to win.

https://i.imgur.com/iudOYJF.jpg

Except it didn't. It only lasted the same length of time as O1. I was confused, and saw this picture and thought the little "comets" at the edge were particles coming out and leaving damage as they left. It also didn't feel as sharp as the other irons while it was wearing, which is counter to what most people would think - and an illustration of how powerful what we think we feel is when it's not differentiated from what we actually are observing. I thought the same thing. swapping irons out back and forth and looking at the actual surfaces though showed it was deficient. Not horrible, but it seems like there is lost potential.

However, there really isn't.

Those comets are stray tungsten carbides. It is probably possible to process this steel perfectly forging, but these irons are strip steel. Most japanese plane irons are strip laminated steel purchased and punched out. If you see a perfectly straight lamination line or close to it and the lamination is thick on a japanese plane, it's unlikely to have been hammered into wrought. It's always possible, I guess, but possible and actual are different.

Larrin thomas showed both japanese steels (like super blue) and some european tungsten steels with high carbon and a similar alloy and found the same thing with all of them. There can be a 100 micron clear expanse and then the next frame on the micrograph has a big 30 micron carbide in it.

Larrin's micrograph page is here:
New Micrographs of 42 Knife Steels - Knife Steel Nerds

it's interesting to see PMs (like XHP/V11) compared to M2, and compared to ingot D2 (terrible!) vs. PM D2 (good!). It lets us see why the ingot common steels of each type are actually really good. Metallurgists had to choose a composition that would behave in an ingot. If large stray D2 like carbides were unacceptable, then you can't use that composition.

That was the last blue steel tool I ever bought. I'd gotten aggravated by a pair of blue steel japanese style planes from brand name makers, seemingly leaving little lines on work, and puzzling about it. It's an artifact of the alloy, which I believe is used because it's easier to heat treat than white steel. Tungsten was initially added to high carbon steel as a means of improving toughness. In something like a W series water hardening steel vs. something like 1095, it probably does a little by giving carbon somewhere to go so that the lattice/fingers that form and intertwine in the steel matrix aren't stopped leading to "plates" from too much carbon remaining. This plate is why 1095 and O1 aren't very tough. they're nice steels, but they don't take much force at high angles to break in a toughness tester. About the same as XHP/V11, and probably the same as M2 high speed steel.

Prepping dirty wood from rough is a probably the optimal place for most of us to employ power tools with structured carbide cutters. For example, I like to joint boards by hand. The power jointers I've used mostly left a scalloped finish which was poorly suited for a glue up. But, they were great for quickly truing things up so I could get to work with my plane.

that or a dedicated jack plane that's easy to sharpen. I shouldn't admit this, but I've got boards that are literally black with metal dust and stuff. They are rough sawn boards, of course. When I need to use one, I brush the dust and dirt off, vacuum them a little bit if needed and employ the jack plane to clean them off to try to get under the crap as much as possible rather than plane through it.

I bought a huge honking makita planer from japan last year, though - it's been difficult to use it accurately enough so that it saves much time over hand jack planing, but it definitely clears the dirt off and I'm not as tired after using it.