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Sure there are… examples of a few
* J.A. Henckel Cermax MC66 knives, e.g. TWIN Cermax MD67
* Search zdp-189 in CKTG site
* konosuke zdp 189

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With that thick behind the edge, it probably will be wedgy for firm & crusty cooked roast. A lazy fat KU, need some trimming 😉

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Thanks Cliff!

I mostly concentrate my tinkering around with 52100 steel (except only a few knives with high alloys m4, 3v, k390, s90v, etc..). No 1095 yet, so I will keep your 1095 ht params in mind and possible add a tiny harmon.

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Cliff – beside sharpening, are you making knives too? Glad to see Joe’s paring knife received high remark from you. I didn’t know he utilized cryogenic (liquid nitrogen involved) with his ht. Maybe you should mention for grain refinement – iirc Joe always mentioned thermal cycling prior to hardening sequence. Also Cryo part of ht wouldn’t has significant benefit to alloy steels.

I am not a metallurgist & confused on how carbide precipitated when your stated soak aim for 0.6% C in solution. Mostly martensite is carbon rich, when carbon leak/migration from matrix to form carbide by precipitation would soften the matrix. Hence wear resistance go up (due to carbides) but will be at the cost matrix hardness (RC). The only scenario I see where one can get harder rc than at quench by having excess retain austenite at quench and then gain extra hardness from cryo lowering RA %.

I enjoy tinker/mangling steels. A friend just filled my 20L dewar for free, in the name of eta carbide science 😀

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To keep things simple in my mind, sometime I am guilty of over-simplified. After spent a bit of time looked at these SEM pics. One can agree that burnishes occurred either during sharpening and or stropping. If a medium/steel capable of having stable stretched & elongated & (idk but plausible) displacement volume, then this behavior COULD taken place at nano stropping level. unless the medium consists of discrete grain/block where impact from stropping never exceeded yield strength. Let’s call this extrapolated deduction :dry:

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ps I’m still curious as to what makes a “laser” a laser?

IMHO – 1 cent worth

Definition of “laser” term is subjective from person to person – whatever fit the bragging right. In general, it means thin spine (no more than 2.5mm for a 45+mm blade width) with zero grind (a giant bevel start at the spine all the way to the edge) and cutting edge is merely a acute angle micro-bevel (well, with subsequent sharpening the ‘micro’ does get bigger).

Looking at Richmond laser pic, their definition seems to be some sort of convex face, which goes steeper near the edge, then a regular cutting bevel. That cutting bevel isn’t micro, which suggest it’s not that thin behind the edge. Even taking possibly its cutting bevel angle is acute.

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You can adapt my freehand burr/wire-edge removal method for WE. Use a solid smooth grain round stick – such as olive wood – to file perpendicular to the edge. Yes, laterally to fold burr and or wire-edge 90* to the apex. Then use WE pull down stroke to cut off the folded-over burr/wire.

Here is a video I posted 8 months ago. This is my go-to deterministic burr/wire removal. Heheh maybe worth a try or :huh:

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60 grit sand/clean: the tang, inside of the ferule, handle ferule neck.
Use 1/4 or 3/16 4″ (or whatever the tang length) drill bit to clean the tang hole.
Pour 1/6 oz (or more if not enough) of a mixture of 2/3 g/flex epoxy + 1/3 saw dust into tang hole. Coat epoxy inside metal ferule & ferule neck. Insert ferfule & tang. Pour more epoxy into hole if epoxy doesn’t spill out when insert the tang. Clean unwanted epoxy. Place knife vertical for 7hrs before f&f touches.

Stab bend knife tang into a green apple or potato, push apple down into the heel. Heat up the tang over open fire to 400-600F, now bend the tang straight. Hammer tap it if it refuses to straighten by leverage. Make a new hidden tang handle out of hard wood (instead of what the original handle appeared to be very soft wood). Have fun carving ‘bread’.

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Good clean work Tuffy.

I am with Curtis & Josh on edge profile & geometry – ‘return’ should be on a straight line from heel-edge. Let’s look at your repaired edge from a cutting perspective:

1. Push down (aka push cut) – not all materials are completely cut under the recurve edge. because of the gap between the edge & cutting board.

2. Pull back (pull cut) – fine.

3. push forth – same as 1.

4. rock & chop – same as 1.

and perhaps note that the chip is probably the most-used area for this user, so a recurve there might negatively affect the knife performance.

A handful of salt goes well with MHO.

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What is an acceptable range of particle size for these products?
It seems to me that a small percentage of oversize particles would dominate the polishing behaviour.

Mesmerized by all those SEM nanographs! Thank you.

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Occasionally I sharpen knives for my relative restaurants. No fancy jknives involved.

In addition to Tom’s points. Bring along a good loupe to inspect their knives & cutting boards. Looking at cuttingboard types + chop/slice/scrape marks + length/depth would reveal quite abit about their knife usage pattern. Your portfolio/sample knives: 1 crazy thin& sharp (don’t leave this one there), 2 durable sharp. I made newb mistake with too thin & sharp, quickly rendered knives worthless dull (from rolled). If jknives involves, how’s your freehand with bench waterstones & jnat?

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Get cheap 1×30 AluminumOxide sanding belt resin cloth back, 40 thru 2K grit. Want ceramic 40-120 grit, get norton blaze belt. Cut & resin/expoxy, then heavy grinding away. Ok to wet grind too. These strips are very durable and will last a long while (many reprofile).

Remember to clean loose low grit/particles to minimize unwanted scratches.

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7* inclusive is my lowest freehand angle on my 24cm v2(steel 64rc) gyuto. Yes was chippy and had a crazy time removing less than 2um tall wire-edge. Ok, that was a little bit passed V2’s steel limit. I micro-bevel around 18* and with subsequence touchups it’s slowly becoming a regular bevel. It would be super cool if WE supports this kind of acute angle sharpening or perhaps too crazy nor practical any way :silly:

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A knife with super sharp + sub 20* inclusive angle + thin-behind-the-edge will easily pass this tomato test. This can be easily verify/reproduce by testing with a feather-brand double-edge (DE) razor. Note: DE edge is highly polished.

Tomato in Kono video is fairly firm. Tomato in Miz video is crunchy… Just pondering how those knives fare against wrinkly riped tomatoes :unsure:

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I am still waiting for some SEM pics from Clay & Sandia to clear up this fuzzy topic. This topic lured me here in the first place – Thanks Anthony Yan 😉

Mean while, just to refresh where my head was… Took 2 box cutter blades. blade1 – stropped on a NEW bare horsebutt leather for 30 strokes at 10 lbs of pressure. Blade2 – stropped on a 7 months USED bare horsebutt leather for 30 @ 10 lbs. Snapped usb microscope 400x for each result. Doh, I didn’t capture a pic for control/untouched blade.

Oh, I remember now. New bare leather won’t do much because a bunch of tiny silicates too small to cause macro (micron level affect). Used leather where contaminated abrasives (dirty fingers :ohmy:)will abrade, while metal particle (from dirty fingers and came off the blade) will burnish. Other physical interactions are interesting but seem unlikely to have major affect in displacing steel matrix – especially high alloy where complex lattices & bonds will certain resist nano-level of molecular displacement/flow.

Just to be obvious – used bare horsebutt leather strop smoothened the bevel. I simple can’t tell how much it burnished but quite sure it did – probably small part by abrasive and major part by swarf.

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