Banned from knife making - rikizai

I will supply an address....

Bill Tindall, E.Tn.

....to where banned knives can be sent. One large chef, one large slicer, medium slicer, one boning, several paring.

Re: I will supply an address....

Bruce McCrory

And, none of the mrs. tomato mashers......

In her defence, I always find myself bleeding in the sink after a sharpening session. My fingers are magnets. I can time the next maintenance tuneup by how long it's been since cuts have healed over.

I'd put an order in to you but already have, to Brand X.

Re: I will supply an address....

David Weaver

no guarantee that any knife that I make won't break out half nickel sections, but I will be buying more rikizai to try more. I wish they made it available to us in VG-10 clad in mild stainless as that would be more practical and over time, I could bargain one into the block.

anything that rusts or discolors is considered untidy by my wife.

Ditto on cuts, but for me, the worst I've gotten is when final grinding blades on a stone. If they roll at all, you can end up with an unsharpened (but sharp enough) blade that catches on the spine and rolls into hands or fingers.

Once I surface finish this knife (which is maybe a waste of time at this point) and handle it, I'll have an opportunity to sneak use with it when the mrs. isn't at home and see how it works. It's absurdly thin (learning experience) and the next one will be a little bit less so. It should be entertaining to use in vegetables.

Cost to make this size knife (about 6") and another petty knife is only about $20 each with material costs included, but the guy who sells the billets has only carbon steel.

I can't say just how novel the ability to tap a hardened and untempered blade into straightness is, though. if that's tried even just a little bit with unclad steel, the knife will break at the tapping point and the end will shoot off. It's extremely handy to be able to do that. I don't ever temper any knives soft enough that they'll ever tolerate that without cladding and am not into the differentially hardened knives (which would be a way to make a solid steel knife easier to straighten without leaving it thick enough to grind out any warp) as the tang/handle area is too soft and the stiffness is lost.

Re: I will supply an address....

Wiley Horne

“ I can't say just how novel the ability to tap a hardened and untempered blade into straightness is, though.”

David,

This is turning out to be very interesting. Your ability to move hardened high RC steel by tapping on the laminated mild steel is similar to ‘tapping out’ a Japanese plane blade as the land approaches the hollow.

I am wondering if the white 2 will sharpen somewhere intermediate between 1095 and the file steel. Hypothesis: White 1 might sharpen about identical with the file steel.

Wiley

Re: I will supply an address....

David Weaver

I think your hypothesis should hold. I remember reading that white 1 is really hard to get right, and the description about it made it out as if it was a quench temperature difficulty, but I gather at this point it's a working temperature difficulty. Just about anything can be heated quickly a notch past critical and quenched fast without too much time for grain growth.

I don't know what japanese makers do now, but I would bet that the best possible plane would be made either with grain orientation and a computerized temperature control process after forging, or trying to forge the grain orientation out of the hardened steel and then doing the same (computerized process).

All of the sources you've pointed me to suggest you can make a fine grain structure by forging, but not like the fineness and uniformity (and ultimate toughness) of normalizing that can be had with a temp controlled oven.

Long and short of it, I doubt I could do anything useful with white 1 over white 2 hammering a few heats at relatively low temp and then quenching, but it would probably still have that nice dry crisp feeling at the edge.

(I'm just guessing that the thing that really makes file steel better for me is carbon, but more importantly, something that slows down transition rate in quench just a little. It hardens unbelievably well in simple soy oil and has that crispness)

Very interesting to experiment with, but the ability (and there was an absolute need with this blade) to be able to straighten after quench is a real time saver. It means that a knife doesn't have to be made fat and then ground very slowly after heat treat to be thin at the end.

I ordered blue 2 and takefu white steel (Which is hitachi white with small amounts of chromium, vanadium and molybdenum) to try. I'm hoping that the latter will warp less. The former should. No stainless that I could find, though, but it would be a bad idea to forge that, anyway.

Slooooow 

David Weaver

I have only a high speed belt, so I spent about two hours today working deep scratches out of this. Traditionally made japanes knives are scraped. I'll be scraping the next one. I realized after about two hours that this is mild steel...it's not ever going to get the super sexy fine finish that wrought iron takes off of a soft finish stone. Will handle and sharpen it soon. It, tempered around 340 degrees and super hard.

Re: Slooooow

Brian Holcombe

Nice looking blade, David!

Re: Slooooow

David Weaver

Thanks, Brian! It's got its warts, but hopefully be usable as a first try and the second one should be better.

Re: Banned from knife making - rikizai

David Weaver

The adventure dealing with white steel in a narrow knife.

I see the draw that the high end makers have (though their ability to forge more probably improves their knives far beyond what I can do just heating and shaping the metal). That draw is to make a harder and harder knife blade as a matter of art, but do so in a way that dime-sized chunks don't come out from unexpected use.

I probably have the rikizai blank around 64/65 hardness - it is nearly unhoneable on a relatively fast cutting suita. This is my acid test for japanese chisels just as the washita is the acid test for western chisels. If a chisel cannot blacken the suita, it's not going to work practically. The same is true for western on the washita, though I'm sure the C scale is a point or two apart for both of these. The magic point is often something like 1 point on the c scale - a blade will completely change its behavior and seem hard and tough at once.

So, if you're some garage hack like me, you don't start at a lower temper temperature (I went around 340-350 for white 2) to try to have some ungodly hardness level, you do it in case the quench was good but not great (if you fall two points short on the quench, then the temper will follow that - you can't make it up in the tempering, it's 2 points lost along the way more or less).

For anything more typical than finding out where this lands before it behaves well (the very tip microchips in sharpening, so it can shave hair, but it never quite gets really sharp, and you can see the evidence under the scope), I'd do like they do with production factory knives - just temper it around 61 or 62 and it would live forever at that.

The forged knives that I saw listed generally went around 63-64 without having to go to exotic steels, and the difference in that must be reorganizing the rolled bar so that it didn't have a grain quite so prominently running parallel to the blade.

I'd be curious to know if the high end makers do a whole bunch of forging and then off the screen, run their blades through a modern temperature cycle to normalize it properly and then quench. In that case, the forging would remove the grain prominence and the normalizing would allow higher hardness than forge to quench would.

I didn't order an oven yet

The mrs. goes grocery shopping in a few hours, so I will be able to temper the knife back to about 370 degrees or so. More confirmation that the absurd temperatures often mentioned for tempering (110C) tools have nothing to do with reality. At 340F or so (Which is at the low end of hitachi's schedule), I can't really even scratch the steel - it's slow even on a fine india stone and loose silicon carbide isn't removing the last belt scratches from the hardened layer.

(but from an aesthetic standpoint, loose silicon carbide is enough to make the mild steel layer uniformly dull looking and do it quickly enough that it's not much trouble in the future. A minute per side would bring the uniform look back if use dings it up. Natural stone slurry on mild steel goes nowhere).

Re: Banned from knife making - rikizai

David Weaver

A good indicator of the high hardness is that even with rolling silicon carbide grit, the blade is attempting to take a partial polish. The camera doesn't pick this up well, I guess it's anti glare. IT's very close to a polish aside from the fact that some of the belt grinding marks persist.

(the reason natural stones go nowhere is that part of the mild steel will burnish and part will less to some extent - the combination look is horrible. When I was buying and reselling stones, one of the constant requests was "give me a fast cutting stones that makes the jigane (soft) uniformly dull and the hagane (hard) bright polish with no visible marks at all".

ahhh..ok. there's various levels of not quite there from "nowhere close and ugly" to "lovely", but nothing that absolutely does that perfectly.

The jigane is so soft on this knife that I worked through it on the back end of the blade. Too bad, that looks bad, but up really close, you can tell this knife started with minor warps. Cucumbers won't know.

The learning is always interesting.

Really beautiful, David!!

Thanks, Wiley!

XHP mule

David Weaver

I managed to make several blades to test how well they'd work in poor-man's manufacturing techniques (for example, open atmosphere with XHP).

I learned more about XHP, which makes the claim of ease of sharpening kind of funny:

1) we discussed before that XHP lets go of its wire edge, which makes it seem easier to sharpen than it is

2) it's the grinding of material away from the edge even in medium honing where people will come up short with it and then think that it's chipped more than it really should be (it does seem to chip small chips easier than carbon steel, but they can be chased out and the chips won't occur in clean wood)

It's a booger to shape on a belt grinder. Not totally intolerable, but half as fast at most on typical ceramic belts vs. the plain carbon steels. There are far worse than it, but the difference between this and a steel without so much chromium is stark.

So, the mule is only a small chopper about 4" long.

The extent of how tough it needs to be after poor-man's heat treat is to stand up to the buffer (sounds like a low test, but high hardness japanese steel in a knife will not allow the edge to be completely refined by the high speed buffer wheel - it's a bit too rough for a thin cross section), not chip in use and to get mildy rough treatment cutting boxes and not show anything on the edge. IT meets that standard. I'd imagine a real knife test would show it to be junk for an enthusiast of knives, but doing any better requires temperature cycling (and a furnace to do it).

All that said, it's brand new with a tiny bevel - otherwordly through vegetables, no strange defects in any of the rough treatment, tolerates the buffer fine and gets sharp and the veggies cut with it have a strange waxy texture on the side where they're cut that creates sensory thrills when eating. Even the cucumber takes some of this on.

It's tough on the ceramic alumina belts, though. A belt that's worn a little won't really cut it well, but will grind and finish a carbon steel knife with plenty of sparking or two yet. I'll make one more in 6" size with a real handle to actually use.