Thread: Coticule - Diamond plate

I just flattened my La Grise with a diamond plate because it was way out of whack.

I then honed on it and disliked my shave, which is very atypical.

Then I read this:

A diamond plate on a coticule will cleave the garnets. Leaving jagged edges which defeats the whole purpose of using a coticule. It is the natural shape of these garnets that give that characteristic coti edge. Some do it though and say it is fine, but not so much under a microscope. Coticule will usually be much faster after lapping till they settle down.

What do we think of this, and if so how do we "fix" this?

Do I burnish them? hone some razors on it dry, use my slurry stone wet/dry? Rub some Coticules against one another?

As I also found this:

A Coticule contains garnets for abrasive medium. When we moist the Coticule's surface and rub it with another piece of Coticule, garnets are released into the water.

Any input is greatly welcome,


In the old video (1970s) I posted about the Coticule, the people used to take GREAT care to finish the stone right, I'm sure they were very knowledgeable about the why they had to do this after the stones were sawn.

Originally Posted by TristanLudlow

I just flattened my La Grise with a diamond plate because it was way out of whack.

I then honed on it and disliked my shave, which is very atypical.

Then I read this:




What do we think of this, and if so how do we "fix" this?

Do I burnish them? hone some razors on it dry, use my slurry stone wet/dry? Rub some Coticules against one another?

As I also found this:


Any input is greatly welcome,


In the old video (1970s) I posted about the Coticule, the people used to take GREAT care to finish the stone right, I'm sure they were very knowledgeable about the why they had to do this after the stones were sawn.

I'm new with a Coti as you know but if it were me, I would probably make slurry to release some of those jagged garnets.

Originally Posted by STF

I'm new with a Coti as you know but if it were me, I would probably make slurry to release some of those jagged garnets.

That's indeed what I was thinking, I can totally understand that a little layer has cleaved garnets.

I guess I will use my slurry stone to remove a few layers of pencil grid lines, thanks!

I used to raise slurry on my coticule with. coarse diamond plate. Now that I think about it, the edges I get after using only my slurry stone for a long while seem much better. I second Steve’s suggestion.

Can't hurt to try working up slurry a few times to wear off any aggressive edge that may have been caused by the diamond plate. I've also improved the result from my coticule by burnishing the stone. There's also the possibility a piece of diamond grit may have broken off and dislodged in the softer coticule material.

I don't know how much flattening was required, but another thing to keep in mind is that these are natural stones and by no means uniform. You may very well have found a layer in the stone that won't perform the same as it did before you took the plate to it. But I imagine that's a rare case unless you see some sort of aberrant spot or inclusion in the stone's surface that hadn't previously been exposed.

Thanks everybody.

Had some visible scratches on the BBW & Coti side of my stone,
raising a slurry and a few rubbings quickly and easily removed them.

It does make sense that the surface garnets are damaged by using the diamond plate, but it cleans up very nicely with the slurry stones.

Thanks for the thread! I bought a coticule a while ago, lapped it, finished a few razors on it and wondered what the fuss was about coti’s. I don’t have a rubbing stone for it. You think burnishing would have the desired effect? Or better just to get a rubbing stone?

Originally Posted by jfk742

Thanks for the thread! I bought a coticule a while ago, lapped it, finished a few razors on it and wondered what the fuss was about coti’s. I don’t have a rubbing stone for it. You think burnishing would have the desired effect? Or better just to get a rubbing stone?

I think a slurry stone would come in handy, I luckily have a few that came with mine;
but I think other (maybe harder) stones could possibly also work to release the damaged garnets. (although I can't tell you for sure how efficient that would be, but I wouldn't see why not?)


In any case, I cleaned my La Grise with the slurry stone and re-finished my razor on it, this time on oil though; but the edge came out very sharp, but very very smooth.

I wish I had tried running water as previously to make a direct comparison, but I think there is truth to the damaged garnets theory.

The sensation was the same now than when I honed on it before, but I could immediately feel on the strops that this edge was much smoother and the shave confirmed this.

Originally Posted by jfk742

Thanks for the thread! I bought a coticule a while ago, lapped it, finished a few razors on it and wondered what the fuss was about coti’s. I don’t have a rubbing stone for it. You think burnishing would have the desired effect? Or better just to get a rubbing stone?

Personally I would get a rubbing stone.

Slurry contains released abrasives(garnets) and cuts faster. I may be wrong but burnishing the Coti sounds counter productive to me, to get a nice finish /polish I use either dry or under running water and then strop on fabric and then leather.

Stropping makes a huge difference to a coti edge.

Just my opinion based on only a few weeks with my Coti.

Originally Posted by STF

Personally I would get a rubbing stone.

Slurry contains released abrasives(garnets) and cuts faster. I may be wrong but burnishing the Coti sounds counter productive to me, to get a nice finish /polish I use either dry or under running water and then strop on fabric and then leather.

Stropping makes a huge difference to a coti edge.

Just my opinion based on only a few weeks with my Coti.

I wouldn't say that it's counter productive, but given the rate they release slurry it's not going to be the same effect as what you'll see with an Arkansas stone. I only suggested it as a method to get the stone to release any grit from the diamond hone or rough/damaged garnets. Using a slurry stone, small Arkansas stone, or something similar and rubbing it under running water to clear the debris should suffice to clean up the surface and is about the limit of how far I would 'burnish' the stone. I guess 'dressing' it would be a better description? But at this point I'm wandering off into the weeds.