Diamond Plate break-in

Presented below are several pairs of images (from the same location) of a new and “broken-in” DMT fine diamond hone (600grit).

New diamond plate.
The diamond plate after five minutes of ” break-in.”
New diamond plate.
The diamond plate after five minutes of ” break-in.”
New diamond plate.
The diamond plate after five minutes of ” break-in.”

19 responses to “Diamond Plate break-in”

  1. Very interesting. So we see dislodged as well as fractured diamonds, do I see that right? Also the intact diamonds don’t show any “load up” or wear.


  2. This is great to see. It is amazing that you can re-capture the exact same spot on the diamond plate!

    From my experience, both the Atoma 140 and the DMT course stones have worn out pretty quickly compared to the Wicked Edge diamond stones. Admittedly I was using a lot of pressure on the Atoma’s but no more than I use on the WEPS ones. The DMT was used w/ light pressure but I did some lapping on it.

    I got about 40 knives out of the Atoma plate before it was not very effective anymore. I only got a few knives out of the DMT plate, but I did use it for lapping as stated. And on the Wicked Edge plates I get about 400-500 knives, given that is for 2 plates on each grit (one on each side of the knife) but still, they have been hands down the best in my experience.

    Thanks Todd!


    • I am surprised that the diamonds on this example are not buried more firmly in the nickel plating. This may be a quality control issue – metal plating is not the easiest process to control, in my experience.


      • They probably plate it with electroless nickel with the diamonds in suspension of the Ni solution the same way that Nickel Teflon or Nickel Boron Nitride is deposited. So the distribution of diamonds should be relatively random. The cross-section in part 2 seems to show this.
        Just a guess though.
        Sounds like a pretty tricky optimization problem, lots of tradeoffs, volume & concentration of solution, the amount of fluid movement needed to keep the diamond (or PTFE or BN) in suspension, etc. I wish I knew more about the process than I do, majored in Chemistry a long time ago, but became a toolmaker and made tooling for parts that got Ni-PTFE coating (M16A4 update in the 90’s)


  3. I wonder if diamonds breaking rather than being pulled out is proportional to impact speed with faster rubbing more breaking ?


  4. I love diamonds for sharpening, but my DMT stones do “break-in” quickly, and in a very noticeable way–although I have yet to declare one dead! Even the “course” that I used on each of my three Spyderco Ceramic stones.

    Speaking of my Spyderco stones…I believe they’ll last forever, but they are painfully slow, and since I won’t last forever: I hardly have any use for them at all. I’m talking about kitchen knives, maybe I’d have a different story if I had a straight razor.

    If I could have diamonds embedded in my Ceramic stones–and actually be flat–I guess I’d have nothing left to wish for.



    • It’s been years since you left this comment but check out Naniwa diamond stones which are what you describe.


  5. Todd, great! I remember asking you about this some time ago, cool to see that you’ve gotten around to checking it out.

    I wish that you would have imaged a VERY worn diamond plate as well. I am pretty sure we would see significant wear/flattening to the ultimate points/peaks of the diamond particles. 5 minutes break in is probably not enough to show this.

    What did your break-in procedure consist of?



  6. This is fascinating. Every time I read a new article on your site I realize I need to correct a YouTube video I’ve published with new clarifying material! Thanks for sharing your resources and wealth of sharpening information Todd!

    If you ever get your hands on a Vitrified Diamond Stone, I would be very interested in seeing whether the pattern seen here holds true in any significant way on a Vitrified Stone.

    Heck, if you just wrote an article that helps us simpletons understand what they actually are & do I reckon that would be very very helpful to many being wooed by the internet mass peer pressure to purchase one.



  7. Amazon has many a chinese diamond stone. I have bought several called Jewbore and like them a lot. I would like to know if they are diamond or mostly diamond. They work on knives @62+.


  8. I’m surprised they don’t do the breaking-in process at the production factory – there they could recover the cast-off diamonds. I just washed all mine down the sink.


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