400 Grit and Microchipping?

[Steve56]

Folks,

I have a 400 grit ceramic stone that I use to reset knife bevels and have used to remove small imperfections from razors. Other posts describe micro chipping from 400 grit stones and I have observed the same from mine under low magnification. Currently I'm testing a 600 Chosera as a possible replacement. I don't know how much of an effect there is, but it's probably not a good thing.

Are there any 400 grit synthetics that cut relatively fast and don't produce that micro chipping or is this just wishful thinking?

TIA, Steve

 

[buca3152]

The size of the particles is working against you. 325 dmt is I believe 45 micrins so that will'leave that size missing in the steel from the scratch pattern. You can remove a lot of metal with a chosera 600 and the 1k cuts pretty fast. I take out chips with a 6 micron(4k) equivalent dmt. It cuts plenty fast and doesnt leave chips and doesnt dish out. Then i hit the chosera 1k and up.

 

[Gamma]

400x of any flavor is harsh to a razor.
After that kind of work - a good amount of time has to be spent on the next stone so the scratch pattern and resulting chips are removed.
I have a 400x C - I use an 800x C after it and it's always a lot of work to clean up.
I try to not use the 400x unless I need to; big chips, etc.
Abrasive type/particle shape and binder composition will play into this - diamonds on a plate are very harsh, other abrasives less so.
Any time I put a razor on a 325x DMT I wound up with a mess that was seemed nearly impossible to clear.
I did clear it up eventually but it was way too much effort IMO.
But - whatever it takes is whatever it takes. Can't leave big honking gouges in the bevel or it will come back to bite you.

 

[Bayamontate]

What Gamma said.

The only exception I've found is the Shapton 500, it plays nice with razors at that grit.

 

[eaterofdog]

When I really need to move some steel I will use a worn out "600" dmt (probably more like a 1000) for 75% of the work and over to the 1000 nani. Diamond cuts clean but it also cuts deep.

 

[Steve56]

Thanks everyone,

I had wondered about the Shapton and the 400 Superstone. Is that the Shapton Pro stone Bayamontate?

I've discovered not to use the 400 unless I had to, but at the time it's all I had below a 1k Superstone. These are not chips in the traditional sense, but tiny perfectly half-round "chips" you can only see well with moderate magnification. They're probably smaller than a hair and I haven't noticed any effect so I'll likely just let them work out over time rather than trying to remove them

But I think my question is answered. Thanks again all.

Cheers, Steve

 

[Bayamontate]

Steve, I have the 500 Glass, IMO, it's more like an aggressive 1K than a traditional 500.

 

[Gamma]

The perfectly half-round chips, is the edge like smiles that are connected, or more like domes that are connected?

 

[Steve56]

They're not connected, just an occasional tiny half-round "chip". Maybe 2-4 of varying size along the edge. They were not there before the 400, and some have been subsequently removed or made smaller of course.

cheers, Steve

The perfectly half-round chips, is the edge like smiles that are connected, or more like domes that are connected?

 

[Gamma]

Ok - was just wondering.
Often, micropitting causes chipping that will be readily visible after honing on lower grits.

 

[Steve56]

Folks,

O.K., maybe another explanation. The blade I'm discussing is a Le Grelot Medal d'Or 1931 blade, and when I received it had very little wear on it, and may in fact have been a NOS blade (I don't think the scales are original). It's in great shape but has a few tiny corrosion pits including a few specks on the bevel, only visible under magnification.

As might be expected for a vintage French blade according to other posts, it took quite some time on coarser stones to bring the bevel into alignment with the spine.

So could those tiny half-round defects I thought were 400 grit microchips actually be where the bevel wear "ran into" a tiny pit?

I can't feel any effect from them in shaving so see no need to put further wear on the razor.

Cheers, Steve

 

[Gamma]

Could be caused by a few things, but yes - same as micro pitting.

 

[SliceOfLife]

Ok - was just wondering.
Often, micropitting causes chipping that will be readily visible after honing on lower grits.

This. I've been honing razors on everything from 60grit garbage pocket knife hones to unknown grit cigar hones to 220grit DMTs and on, and I've seen zero evidence that this low grit micropitting problem is ANYTHING other than pitting that was not visible on the bevel at higher polish being revealed as gaps in the edge as the bevel is pushed back. Given the right circumstances you can even get holes on the bevel ABOVE the edge, as in the edge is clean and straight and there is an actual 360 degree perfect circle BEHIND the edge from that point in the bevel being cut thin enough that a spot of pitting punches all the way through. I have yet to find a stone that actually causes chipping in razors due to its particular particle size or abrasive.


And yes Steve. Those -It looked NOS with just some slight pitting evidence- blades are the worst offenders for this sort of thing. Most likely it got a pretty heavy restore job after being pretty seriously pitted. Guys good with polishing wheels can remove and/or cover up some pretty insane pitting and still leave a blade looking almost as good as new (key word being looking). I'd say it's a good bet that if you pushed the edge back a good 2-3 mm this "chipping" issue would go away.

 

[buca3152]

Im not an expert but have seen exactly that with a scope and a loupe. Honing with a 325 or coarser dmt leads to microchipping in my experience. The blades almost always chip with a 325 and almost never chip without it. Coincidence? I dont think so. I dont use anything under 600 grit on a razor unless i want to spend more time cleaning it up than the time i saved using it.

 

[Obiwan]

I have a DMT 220 that I've used when needed on razors. For me, it's never caused a problem in progression. Maybe I've been lucky. I've followed with a DMT 325, then 600 then chosera 1k. The DMT saw much mileage as a lapping plate first so maybe that helped settle it down a bit.

 

[jpcwon]

I recently used my DMT 325 to re-establish the shape of a bevel after bread knifing a razor, and no microchipping was observed. My DMT, like Obiwan's, is worn-out though, so that may have helped to tame things a bit....In all honesty the only microchipping I've encountered was linked to micropitting near the edge; not as a result of the stone at hand....That's just me though...

 

[Steve56]

Thanks everyone,

The blade in general, has little pitting, just one patch on one side well up the blade and none behind the bevel. Most of the original finish is there, it hasn't been mirror polished. But there are some pits ON the bevel, tiny specks. I was reading a stropping thread and Kent commented that he could never get a bevel clean by wiping, it always had "shaving schmutz" on it unless he cleaned by stropping. I though I was the only one who saw that, but I've had the same experience. And that's what this reminds me of except there are little pits that look like where little pieces of debris might have been.

The blade might have been restored, the tang is a little concave and the Le Grelot bell is almost gone, and the tang IS polished. Very little hone wear and an original box in great shape. And the crudest, ugliest, non-original scales you've ever seen that seem a bit too narrow for the blade. But this was the middle of the Great Depression, so maybe they used what they had. Probably not but who knows.

I've learned a lot from it and its a really nice shaver, sort of like an old pair of blue jeans.

Cheers, Steve

 

[drmatt357]

I have a DMT 220 that I've used when needed on razors. For me, it's never caused a problem in progression. Maybe I've been lucky. I've followed with a DMT 325, then 600 then chosera 1k. The DMT saw much mileage as a lapping plate first so maybe that helped settle it down a bit.

+1 here for sure. I most always use my Atoma 400 for bevel setting. I think what may appear to be micro chipping is really just a rough toothy edge. I do then follow up with a conversion stone after the diamond tho.

 

[Gamma]

Micropitting is often not visible without high-level magnification - 200-400x.

Schmutz or no schmutz, steel can pit. Schmutz will probably exacerbate the issue though.
My first run in with this was when I was just starting to hone.
I had a Torrey that would not keep it's edge - I explained the condition of the edge to my honing mentor and me said I described the end-result of honing a micropitted blade perfectly.
That bevel looked 'perfect' at 10x, except for the 'chips' at the very edge.
Oddly - the edge would take shape and the chipping would go away until the final stages.
During the mid-range work it seemed fine.

 

[Steve56]

Gamma,

That's close to my experience here. Alex got me back into straight honing as a honing technique thing, and I've loved it. Not to mention really close comfortable shaves.

Honing a straight is really different. I can sharpen a Shigefusa or Takeda sharp enough to push cut toilet paper or shave with, but the shave is lousy because the edge geometry is wrong. That's what I think Murray Carter called "circus act honing".

Ive honed two straights so far and it really is quite easy. The whole thing as has been posted here many times is that the bevel has to be aligned with the spine and absolutely perfect coming off the bevel setter. If you have that, it's surprising how little else you need to get a shaveable edge. But if it isn't perfect off the bevel setter, don't waste your time, whatever you do won't work very well.

Cheers, Steve