grit vs microns vs mesh. pain in the butt.

[bucketstove]

And i'd love to meet the master knifemaker who can sharpen a blade to hair popping sharpness using a concrete block. I've heard this before and i think this phenomenon is more myth than reality. Much more.

There are videos so myth busted

 

[wvdavidr]

What percentage "off" would you consider "tolerable?" If you wanted 3 micron, would 10 percent of 3.5 micron be acceptable?

 

[bucketstove]

So many "pro micron" guys chimed in i thought surely one of you would know something of the process of how these micron size particles, which are 1/5 the size of a red blood cell and not visible to the naked eye, are made.

Um, first they bake/smelt/purify the material into giant brick
then they smash/crush it into pieces/dust
then they sieve/filter the pieces/dust through mesh/sieve into buckets
what you end up is with a bucket of 36 grit, ....

 

[robgmn]

So tell me, how do these manufacturers create micron size particles? Are they created uniformly?

And i'd love to meet the master knifemaker who can sharpen a blade to hair popping sharpness using a concrete block. I've heard this before and i think this phenomenon is more myth than reality. Much more.

Well, they are ground down from larger materials and screened (think of a sifter with multiple layers, each one having smaller sized openings) until the sizes needed are separated out.
Not a terribly difficult concept or process when you think about it (and let go of what you THINK you know).

BTW - baby powder is 10 micron, and they make that pretty darn consistent (blood cell is 8 micron).
I used to sell abrasives in common sizes of 63 micron down to 45 micron. And yes, my clients knew when the sizes were wrong (i.e. when a screen allowed largeer particles through).

As for sharpening on a concrete block, video proof for you by a master cutler and bladesmith: https://www.youtube.com/watch?v=CXLaE1JvQ94
For his bona fides: http://www.cartercutlery.com/about-us

Any other questions?

 

[jc57]

Larger abrasive particles are separated into different sizes using a series of mesh sieves. Hence the relationship of mesh sizes to particle sizes. Think of a series of increasingly finer screens.

Smaller particles are sometimes separated out using sedimentation, and the application of a physical law (Stokes' Law) which describes how particles sink in a liquid.

Here's an overview that talks about the sieve process:
http://www.engis.com/pdf/Particle-Size-and-Size-Distribution-of-Superabrasive-Powders-summer07.pdf

There are many companies all over the world that specialize in selling sized abrasive particles, including sub-micron diamond and CBN. It is a big industry and there are ISO and ANSI/NIST defined processes and regulations that mean you are pretty much getting whatever size abrasive product they say you are, assuming you are dealing with a legitimate company.

 

[RevDevil]

It's really not productive when you have someone asking a question.
The answers and opinions start rolling in.
People get upset, insults start flying.
Arguments begin, no answer is good enough.
The topic switches from grit vs micron to "it's all BS and stupid".
So we close this thread and chalk this up to more BS and behaving dumbly. Congrats.