Again though, as a disclaimer, I've only used even these on AISI W1 and W2 (not white 1 and 2) tool steel hardened and tempered to around 62+ Rockwell. That's one reason I was curious about the chipping thing Jon was talking about.
yeah... its not all diamonds... just very coarse ones that are electrically plated onto a metal surface... they dont move around like ones in slurrys and pastes, have more exposed surface area, and cut much deeper because of it. This can cause stress fractures in some cases and in some steels. Most other diamond uses are totally fine.
I don't use them on everything, but I've been pretty happy with the results of Dmt fine and extra fine "stones" on Aeb-l and m390. I did 2 identical scimitars for my butcher, finished one on a 2k Green brick and one on the Dmt 8k (xf). He picked up both knives and felt the edges, looked at me and said , "this one doesn't feel like your sharpening" like it was dull. I just told him to try it on something. Then he chuckled. It was finished on the Dmt, too refined for his taste on that kind of steel , but very easy to use. I'll try the fine Dmt for him next time.
Years ago Murray Carter questioned me about my use of the DMT XXC plate for initial edge creation. He wasn't fond of the idea and mentioned how he believed that diamond plates had the ability to damage an edge. I listened but honestly I blew him off and kept using diamond plates on my edges. Then about a year or so later I had a couple of bad incidents that made me re-think the diamond plate thing.
What happened in both cases (gyuto & yanagiba) is that the edge chipped out right on the plate while I was working up a burr. As I recall the gyuto actually made a sort of ping sound when things went south.
Back then I had a little USB microscope set up so I took a look at the damage trying to figure out what happened, looking for a clue, as I was puzzled. I did have Murray's words creeping into the back of my mind right about this time too. What I saw in both instances (done at different times) was that there were deep grooves cut in on both sides that lined up perfectly to make the edge so thin in that one exact spot that it fractured. At first I wasn't sure what I was seeing, on the yanagiba, but when the gyuto happened just like a month or so later I was pretty sure what was going on. In my opinion, it was the combination of the DMT XXC 120x plate, the thin hard edge, and too much pressure being exerted by myself that caused the perfect storm to go down.
So I quit using diamond plates on edges and I've never had this happen to me since.
Lesson here? Don't use really XX coarse diamond plates on Japanese knife edges. I think one of less coarse models would be OK as long as you're not leaning super hard on it. The XXC DMT is bad news for edges, it's just way too aggressive for this task.....oh and Murray was right.
I'm still hoping to find a use for it though...I'm just not sure what yet, lol.
What is approx. grit on XXC.I use a Atoma 140 to thin behind the edge,mostly on Dull Stainless knives.Then Atoma 600 to take out scratches.Never used finer plates prefer whetstones.Don't like Diamond steels at all,seen too many edges messed up wt. them.
From what you guys are saying esp. fine thin edged Japan blades better not to use diamond plates
XXC is 120 grit. Like I said, it leaves a rougher finish than a fresh 36 grit belt.
For sharpening, the EF (1200g), and EEF (8000g) seem to do wonderfully.
The DMT D8XX (sometimes referred to as the XXC) is 120 mesh (120 micron), roughly equivalent to 120 grit.
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