Diamond Spray vs CBN

L

leozinho

Joined
Jan 7, 2005
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Looks like the old Hand American diamond sprays are available again. (I think supply has been hit or miss the last few years.)

If I'm not mistaken, they were the cat's pajamas a few years ago among those that really attempted a keen edge. They seem to have been overtaken by CBN emulsions/sprays in recent years.

I have used some budget diamond paste of various grit sizes with good results (much much better than green chrome oxide), but you can never be sure of concentration or grit size control. I'm wondering if the reputable Hand American diamond spray is worth trying (besides the cost of the spray, I'll need a few more strops too.)

Or just bite the bullet and get CBN.

CBN is a good bit more expensive.

Thanks.
 
I can't compare to same grit size- but I have 1 Micron H/A diamond Spray and 16, 8 micron CBN emulsion from Ken Schwartz. Both seem to work well in their applications. Those CBN emulsions will bring back most of my full height grind convex knives in the field, and the 1 micron spray is great to follow up a coarse DMT stone for S30V.

When I run out of the CBN, I will buy more.

When I run out of the diamond spray, I will look at CKTG's diamond emulsion, simply bc I don't care for the spray atomizer at all.

Hope this helps a bit.
 
Functionally there's not much difference between CBN and diamond. In industry CBN is used when mechanically grinding iron, steel, or nickel alloys because when diamond heats up it can leach carbon into those metals, which causes issues. For hand sharpening they're pretty much indistinguishable. Their grain shapes are incredibly similar.
 
Mo2 said:
ive heard, and i quote "CBN is not higher performance but making a scratch pattern better than diamonds."

but im not sure if this is universal or just for this one particular case that it was brought up in (CBN sharpening stones, so take with a gain of salt https://www.bladeforums.com/threads/gritomatic-cbn-sharpening-stones.1508352/page-2#post-17427417 ).

also i read somewhere to use cbn for carbon steel.
Click to expand...

I'm pretty sure that the reason for the CBN making a better scratch pattern than the diamond is because the CBN is bonded while the diamond is coated. Coated abrasives have much higher grit protrusion and so will scratch deeper than the same grit in a bonded abrasive.

It's also possible that the specific grades of both diamonds and CBN used in those particular stones are different enough from one another in their configuration to cause some observable difference, but that's less about CBN vs diamond in general and more about the behaviors of those two specific grain types.

As far as cbn for carbon steel, you may have misinterpreted (or read a post by someone who misinterpreted) the use of SBN in industry for grinding ferrous metals to prevent carbon migrating into the workpiece like diamond will do.
 
FortyTwoBlades said:
I'm pretty sure that the reason for the CBN making a better scratch pattern than the diamond is because the CBN is bonded while the diamond is coated. Coated abrasives have much higher grit protrusion and so will scratch deeper than the same grit in a bonded abrasive.

As far as cbn for carbon steel, you may have misinterpreted (or read a post by someone who misinterpreted) the use of SBN in industry for grinding ferrous metals to prevent carbon migrating into the workpiece like diamond will do.
Click to expand...
Thanks, good explanation. also about the carbon/cbn you're probably right, it was an old post i barley remember. just did a search and found it here:
https://www.bladeforums.com/threads...damerican-diamond-spray.972264/#post-11063069
 
Boron carbide is different from cubic boron nitride. It's not as hard as CBN is (Knoop hardness of 2750 vs. 5000) but is harder than vanadium carbide, still (Knoop hardness of 2660.)
 
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