Maxamet - Which fine-grit stone?

C

Cementite

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Oct 10, 2023
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Hey, all, I recently purchased a Spyderco PM2 in Maxamet. I am unfamiliar with sharpening the super steels, but I've heard you need diamond plates or something very hard to sharpen high-carbide steels like Maxamet (apparently it has something like 22% carbides with 6% vanadium, 4.75% chrome, 13% tungsten and 215 points of carbon, along with some other stuff)...

I currently have a DMT Dia-Sharp diamond combo plate (325 and 600 grits) but if I want to refine the edge further after the 600 grit diamond plate, do I need another, finer, diamond plate for Maxamet -- or can I use something like the Shapton Kuromaku 1000-grit ceramic waterstone (actually about 700-800 grit according to many users) or possibly the Spyderco "medium" ceramic bench stone, which I believe leaves scratches around 1200-1500 grit? (I already own those two ceramic stones but have not tried to sharpen the Maxamet on them yet.)

I've heard things about "carbide tear-out" etc if you try to sharpen Maxamet on anything softer than diamonds...can anyone give this newbie any guidance on a 1000 to 1500 grit abrasive for Maxamet? Do I need another diamond plate like (for example) a DMT 1200-grit/9 micron diamond plate for the Maxamet? Or will one of those ceramic stones work?

Also, does anyone know whether a Hard Black Arkansas stone (novaculite, about 2500 grit equivalent) will work on Maxamet?

Thanks in advance for any help.

C
 
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Since you have the two ceramic stones. Give them a try and see if you like the edge you get. Worst case is, you will have to resharpen with something else. My guess is it will work fine. You won't damage your knife if it doesn't. It just won't be as sharp as you want, or maybe won't stay sharp as long.

O.B.
 
Diamonds are useful for steels like Maxamet because some of the carbides in the steel are harder than conventional ceramic abrasives. Diamond (or CBN) will cut faster and give a better formed apex because those abrasives do cut the very hard carbides in the steel. I would not recommend using natural stones on Maxamet.

1200 grit diamond would be a good edge. You may be able to get a workable edge from your ceramic stones but it will take longer, wear the stones faster, and ceramics just aren't the ideal abrasive for Maxamet if you want the best from it.
 
I actually have a similar question, so perhaps I can avoid creating a new thread: I also want to buy a finer grit stone for a TSprof. There are the 5 basic diamond stones which are included, up to 1000 grit. TRprof themselves offer many stones. I wanted to get a stone between 2000-3000 grit. Is it best to go with one of the diamond stones, or a ceramic one? Will I need something in-between the 1000 and 3000 grit? Thanks.
 
You'll want diamonds or CBN for sure if you don't want to get frustrated. Something in that grit range you're wanting I'd look at the Venev F400-F800 grit stones. They're resin bonded so they won't be quite as aggressive as a diamond plate like the DMT, but they'll still sharpen the super hard carbides just fine since they're also diamond abrasive. The F400 by itself is a nice working edge and would be in between a DMT Fine and Extra Fine for reference, according to the the gritomatic chart I'm looking at. F800 would be between the Extra Fine and Medium Extra Fine DMT.

Haven't had any issues sharpening up all my Maxamet Spydercos on the Venev stones. Won't take forever either thanks to the diamonds.
 
The common wisdom is that you'll need either diamond or CBN but once you've got the edge bevel and apex sharp, fine ceramics can be used if you want to refine it. I personally don't do it this way but I know of a few sharpeners that use hard ceramic stones on steels like Maxamet and get great results. Give it a try and see how you go.
 
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