Anyone else getting micro chipping sharpening K294?

[kennbr34]

Curious if it's just mine or if anybody else has observed it. I am grinding at 15 degrees per side (12 degree wedge plus the 3 degree primary blade grind) and on an Atoma 140. It seems to settle out when going up to a higher grit, but with a 120x loupe I definitely noticed a lot of micro chipping even up to a 2k Shapton hone.

[RustyIron]

I've neither sharpened K294 nor used an Atom 140, but what you describe is not unexpected when sharpening some of the harder steels with coarse diamond plates. I can pick out a knife and a stone and reproduce the effect in minutes. It's that predictable.

Because of this phenomenon, I avoid using super coarse stones unless it's really necessary. Diamond matrix stones are a little gentler on the steel and are less likely to beat up the edges. A gentler touch with your diamond plates will help mitigate the problem. When hogging off a lot of material and the resultant chipping is unavoidable, expect to spend more time with subsequent stones in order to get rid of the big gouges left behind.

[kennbr34]

I've neither sharpened K294 nor used an Atom 140, but what you describe is not unexpected when sharpening some of the harder steels with coarse diamond plates. I can pick out a knife and a stone and reproduce the effect in minutes. It's that predictable.

Because of this phenomenon, I avoid using super coarse stones unless it's really necessary. Diamond matrix stones are a little gentler on the steel and are less likely to beat up the edges. A gentler touch with your diamond plates will help mitigate the problem. When hogging off a lot of material and the resultant chipping is unavoidable, expect to spend more time with subsequent stones in order to get rid of the big gouges left behind.

Yeah the weird thing is I haven't noticed the same from 15V or from CPM 10V. The Atoma 140 is the only coarse hone I really have that sharpens these steels well, versus just burnishing them.

[Bolster]

What is the difference between "micro chipping" during sharpening as described above, and the "micro serrated edge" that is highly valued by some folks on this forum who do a final sharpen with coarse grits? Is it the same thing with different terms, one negative and the other positive?

Not a rhetorical question: I actually don't know.

[Wandering_About]

I try to avoid putting an actual apex on an edge with an Atoma 140 because it makes such a messy, ragged apex for me, regardless of steel. I'll move up to 400 grit before trying to make an apex, personally.

[Ramonade]

What is the difference between "micro chipping" during sharpening as described above, and the "micro serrated edge" that is highly valued by some folks on this forum who do a final sharpen with coarse grits? Is it the same thing with different terms, one negative and the other positive?

Not a rhetorical question: I actually don't know.

The micro-serrated edge expression some people use is referring to something that can't be seen with the naked eye while micro chipping is referring to chipping that can actually be seen with the naked eye. The micro is a bit exaggerated on the second expression, but it gets the message through : there's chipping but it's smalll

I haven't had time to reprofile my K294 Mule yet (I usually make my handles first) but I've had micro chipping while sharpening S110V and K390. Everytime it either occurred only during the 2 or 3 first sharpenings, or for the very first time it happened, I was using too much pressure while sharpening. Tends to happen while trying to get rid of the burr. Keeping the burr minimal might help

[RustyIron]

What is the difference between "micro chipping" during sharpening as described above, and the "micro serrated edge" that is highly valued by some folks on this forum who do a final sharpen with coarse grits? Is it the same thing with different terms, one negative and the other positive?

Not a rhetorical question: I actually don't know.

Then this must not be a rhetorical answer, as I really don't know either. But here's my hypothesis.

If you look at normal sharpening under a scope, you'll see a bunch of parallel cuts, as if it was done on a teeny-tiny planer. You know, a metal planer with a single-point cutter.

If you look at an edge done with a lot of pressure on a super-coarse stone, you'll see what looks likes a lot of chips at the apex. Chips ain't sharp, and it's hard to polish them out.

I suspect that if you have a good enough scope that you'd see a similar effect with fine grit stones. There's always going to be a bit of raggedness if you have a powerful enough scope to see it.

[u.w.]

What is the difference between "micro chipping" during sharpening as described above, and the "micro serrated edge" that is highly valued by some folks on this forum who do a final sharpen with coarse grits? Is it the same thing with different terms, one negative and the other positive?

Not a rhetorical question: I actually don't know.

The micro-serrated edge expression some people use is referring to something that can't be seen with the naked eye while micro chipping is referring to chipping that can actually be seen with the naked eye. The micro is a bit exaggerated on the second expression, but it gets the message through : there's chipping but it's smalll

I haven't had time to reprofile my K294 Mule yet (I usually make my handles first) but I've had micro chipping while sharpening S110V and K390. Everytime it either occurred only during the 2 or 3 first sharpenings, or for the very first time it happened, I was using too much pressure while sharpening. Tends to happen while trying to get rid of the burr. Keeping the burr minimal might help

I'm not so sure his are visible with the naked eye; as he wrote in his post that he is seeing them with the use, or aid, or a 120x loupe.

u.w.

[Ramonade]

I'm not so sure his are visible with the naked eye; as he wrote in his post that he is seeing them with the use, or aid, or a 120x loupe.

u.w.

Touché, I guess we'll know when he replies. When it happens during sharpening, I know it immediately because of the sound it makes. It feels like the "ting" you don't want to hear when you quench a blade, the moment the sound occurs, you get goosebumps !

[Deadboxhero]

Curious if it's just mine or if anybody else has observed it. I am grinding at 15 degrees per side (12 degree wedge plus the 3 degree primary blade grind) and on an Atoma 140. It seems to settle out when going up to a higher grit, but with a 120x loupe I definitely noticed a lot of micro chipping even up to a 2k Shapton hone.

Rule out burr, specifically a straighten out burr that's blended into the apex.
Rule out scratches being too deep on the 140 grit diamond coated plate.
Rule out soft alumina ceramic stone abrasives.

Try Gunny Juice 0.5um on leather.

[kennbr34]

I'm not so sure his are visible with the naked eye; as he wrote in his post that he is seeing them with the use, or aid, or a 120x loupe.

u.w.

Touché, I guess we'll know when he replies. When it happens during sharpening, I know it immediately because of the sound it makes. It feels like the "ting" you don't want to hear when you quench a blade, the moment the sound occurs, you get goosebumps !

Yeah, I am using a 120x loupe to see them. I can just barely make out the reflection of them with my naked eye, but it takes magnification to tell they're chips.

Rule out soft alumina ceramic stone abrasives.

I am guessing that a Shapton Kuromaku 2k falls into that category?

It's weird because I have used the same hone on other steels I mentioned and didn't notice the same results.

I think maybe it could be the 140 scratch pattern being too deep, because they seem to be concentrated nearest the heel of the blade where it seems to have given me the biggest trouble getting the bevel fully ground, but there's also a lot further up the blade as well.

[Guts]

Didn't get any chipping when I sharpened up my K294 mule using Venev F240 (~45 micron) as the starting grit, verified with a Carson 60x microscope. I'm guessing F240 is nowhere near as aggressive as the Atoma 140 though. I'd always get micro chips with my extra-coarse DMT plates (60 micron) when I used to use those, so I'd bump up to the coarse plate (45 micron) for reprofiling as the lowest grit. Wouldn't get any chips that way. The resin bonded are a little more forgiving compared to any diamond plates however.