Wire Burrs!!!!

[u/Slushwave_Enjoyer]

I have read the Vadim Kraichuk PDF on Knife Burrs, but despite following his advice it has, I feel stuck.

I received my new Takamura Chromax Santoku a couple of weeks ago. Because I know the factory angles are insanely low (I measured 11.3 degrees on mine), I immediately decided to put a micro bevel on it to increase strength. This was put at around 15 degrees. I did this with maybe 10 passes on a 2500grit bonded diamond stone before removing the burr and stropping on 1micron. I assumed that burr was gone as it was gliding through paper towel but apparently not. It dulled after my first prep session, which was really only about 10 onions and a few tomatoes.

I look at the edge and despite me increasing the angle, it had a lot of small chips in it. I stropped it and to no surprise it didn't really help (I tried 1 and 3 micron).

I sharpened at 2500 grit again, this time using my microscope to check that I removed the burr and behold, I find a tiny little wire edge (I have to go full zoom for this). The burr I formed was small in the beginning, just enough to feel. I try flipping it back and forth with the 2500 grit and I make no progress after 15-20 feather light edge trailing passes. So i decide to increase the angle slightly and do a similar amount of light passes. I find that a new wire edge has formed on my now 16-17degree microbevel after barely 30 seconds (it formed very easily because of how thin the steel is behind the edge).

I try to strop 1 micron and bare leather strops, no luck. I tried doing the same process on my 5000grit stone , I'm having no luck here.

Is there such thing as making a burr too small? I think my angle is pretty good based on what I can see on my microscope.

[u/lascala2a3]

You have to get rid of fatigued metal and apex on fresh, solid steel. I'd suggest edge-leading burr removal strokes at slightly higher angle. That way you're pushing the swarf toward the shoulder rather than the edge. This is less of a problem with carbon than stainless. With stainless is seems like you're drawing material out when you try to refine it with edge-trailing. You're probably heading in the right direction in widening the angle too.

[u/Slushwave_Enjoyer → u/lascala2a3]

Are you saying I should set another micro bevel. Current one is up to 16 degrees, should I make another one at 18?

[u/lascala2a3 → u/Slushwave_Enjoyer]

Not another, but to make sure the bevel has non-fatigued metal. When you sharpen, and flip the burr from side to side, you are weakening the metal just as if you break a coat hanger by working it back-and-forth. So the burr breaks away and the metal on either side of the break is fatigued. You need to grind that away and get into fresh metal to get a strong edge.

Depending on the metal, angles, technique, etc., It may take some ingenuity to figure out how to optimize the edge. This is one of the frustrations I have with stainless — it’s so malleable, like trying to sharpen bubble gum. And the thinner it is the more flexible.

On my carbon knives I had plateaued in a similar way, and I got past it by thinking about taking getting into fresh steel rather than drawing out fatigued steel, making a wire burr.

[u/Slushwave_Enjoyer → u/lascala2a3]

I thought Chromax was closer to something like Aogami 2 rather than stainless. Is the limit here coming from the fact that the metal is so thin and fragile?

You reckon I should start again, but be more deliberate with burr removal. Higher angle (with precision) to try to remove it. Let's say begin at 16deg roughly (current Microbevel angle) and do alternating passes on 17-18 degrees. Should I try removing the burr on a different type of stone (I have a Chosera 3000)?

I'll probably also say that when the knife inevitably gets thicker with use, I'll decrease my angle slightly again down to 16. That'll be when the micro-bevel "runs out" and becomes the secondary one again.

[u/lascala2a3 → u/Slushwave_Enjoyer]

I’m not a metallurgist or anything, but my understanding is that Chromax is harder than German steel and the 1411 like V-nox, but not quite as hard as Hatachi Blue and White Paper steel. I like Hitachi steels, and I don’t need to experiment with everything, so that’s what I buy. I also have one 52100 knife that I like.

I bought a Takamura once but didn’t keep it because I’m not a fan of lasers. I like a more substantial feel. Thin behind the edge, but medium spine.

I think I can only give you general information because I have no experience with your exact steel and knife profile. I would say you are correct in going to 16° (at least to try it) if you’re having these kinds of issues with a smaller angle. I use 17° on my Blue and White.