Hand Tools

Subject:
Diamond wear
Response To:
Re: Not making sense.. ()

Patrick Chase
It makes perfect sense if you've actually looked at it in any depth.

Monocrystalline diamonds (and CBN) do wear at the tips. Look closely at this monocrystalline particle from a broken-in DMT #325 for example:

https://scienceofsharp.files.wordpress.com/2015/09/dmt325_brokenin_03.jpg

There is a "before" shot in that blog post as well, but the short version is that the exposed corners do break down, and quite dramatically. That's one of the causes of the dreaded "diamond plate slow-down effect". CBN is known to be worse in that regard than diamond, due to its lower hardness (about 2/3 the hardness when comparing synthetic monocrystalline diamond to synthetic monocrystalline CBN).

They key thing to realize is that "monocrystalline" doesn't imply a single perfect diamond lattice. It just means that the bonds between regions are metallic (crystalline). Synthetic monocrystalline industrial diamonds are both softer and more friable than natural ones, though far less so than resin-bonded polycrystalline ones.

You can get some idea of the factors in play by reading manufacturers' literature, for example: https://www.hyperion.sandvik.com/en/products/diamond-and-cbn/diamond/micron-diamond-cbn/diamond-micron-powder/metal-bond-diamond-micron-powder/. All 3 grades there are nominally "monocrystalline" (metal-bond) but differ appreciably in cost and hardness. The compounds I use are "SJK" grade, and I think that most plates on the market are similar.

If you look around you can find suppliers like Precision Surfaces and McMaster selling natural diamond powders for lapping super-hard materials like solid carbide. The reason is that economical synthetic diamonds simply aren't up to the task.

So with those details out of the way, what I said stands: Diamond crystals do wear out by breaking down. CBN is worse in that respect than diamond.

Messages In This Thread

flattening Waterstones- shapton pro
Re: flattening Waterstones- shapton pro
Re: flattening Waterstones- shapton pro
Re: flattening Waterstones- shapton pro
Re: flattening Waterstones- shapton pro
Flattening
Revise atoma price...
Re: Revise dia-sharp price...
Diamond plates
Re: Diamond plates
Diamond plates......
Re: diasharp vs. diaflat
Re: diasharp vs. diaflat
Re: I think...
Re: I think...
Re: flattening Waterstones- shapton pro
Yes, this
lapping film?
Re: lapping film?
Re: lapping film?
you are not kidding!
Re: lapping film?
A different perspective *LINK*
Re: A different perspective
Not universal preference
to date
Re: to date
Re: to date
Re: to date
Re: to date
:) *NM*
Re: to date
Re: A different perspective
My Opinion...
Re: My Opinion...
My thoughts
Re: My thoughts
Re: My thoughts
The flat wheel surface - or not..
Re: The flat wheel surface - or not..
Re: The flat wheel surface - or not..
Re: The flat wheel surface - or not..
CBN and grit
How Are You Cleaning The CBN Wheel . . .
Re: How Are You Cleaning The CBN Wheel . . .
Re: How Are You Cleaning The CBN Wheel . . .
Why grind unhardened steel on CBN?
Re: Why grind unhardened steel on CBN?
Re: How Are You Cleaning The CBN Wheel . . .
Re: A different perspective
Re: flattening Waterstones- shapton pro
Quick and dirty summary:
Re: Quick and dirty summary:
Atoma - $64
Re: Atoma - $64
Sandpaper Flattening & Shaptons
Re: Sandpaper Flattening & Shaptons
Re: Sandpaper Flattening & Shaptons
Re: Sandpaper Flattening & Shaptons
Stearate coating
Re: Stearate coating
Re: Stearate coating
Re: Stearate coating
Plastic laminating sheet
Re: Stearate coating
which side to use?
Re: which side to use?
Re: which side to use?
Re: which side to use?
a little bit the Indian and a little bit arrow
Re: a little bit the Indian and a little bit arrow
What a great thread this has been.....
Re: What a great thread this has been.....
Re: What a great thread this has been.....
Re: What a great thread this has been.....
Traditional Method
Re: Traditional Method
Re: Traditional Method
Re: Traditional Method *LINK* *PIC*
Re: Traditional Method
Re: Traditional Method
Re: Traditional Method
Re: Traditional Method
Re: Traditional Method
Re: Traditional Method
Re: Traditional Method
Re: Traditional Method
Re: Traditional Method
Re: Traditional Method
My apologies for being a bit too harsh..
Re: Washita vs soft Arkansas stones...
Re: Washita vs soft Arkansas stones...
Re: Washita vs soft Arkansas stones...
Re: Washita vs soft Arkansas stones...
well then....
Another possibility presents itself......
CBN plates
Re: Not making sense..
Diamond wear
Re: Diamond wear
Re: Diamond wear
Re: Diamond wear
Re: Not making sense..
Re: Not making sense..
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