Thread: A theoretical discussion about honing particles

Hi guys, I deleted an insulting post, and asked the poster to simply not participate if he thinks a topic is boring, and not to belittle those who enjoy it.

I deleted the post because I don't want people (esp newbies) to feel discouraged from discussing every last minute detail of honing (or whatever else). If you wouldn't feel comfortable discussing those things here, then where else would you?

I also deleted a couple of follow up posts that responded to that original post. Not because I don't agree, but because they don't make sense without the original post, and also because I don't want this thread to contain a large offtopic tangent that detracts from the original discussion, and might even unravel it completely.

As you were. Have fun

Originally Posted by blaireau

There are standard ways to relate Grit, Mesh and Particle Size. Please see the table below, it's just that simple. Bart, please don't burn up your slide rule on this one, it has all been worked out! Enjoy gents.

Originally Posted by blaireau

I posted a conversion table of American grit, Mesh and Particle size earlier in this thread. The mesh numbers are the range of particle sizes in microns since meshes at these small sizes don't exist. Mesh is a theoretical calculated number not a screen since as I said, meshes of this size don't exist. So, an 8000 grit has a mesh or range of particle sizes form 2 to 4 microns and an average particle size of 3 microns. Above 400 grit, particles are not seperated by actual meshes but by other processes which are mostly of interest to mechanical engineers involved in grinding technology.

So in my browsing for stones I've noticed that all the ones I've looked at list the specs for a stone in both grit and microns. Actually I got the impression that maybe the grit was more of a "name" for a loose comparison. For example:

Shapton (glass) 8000: 1.84u
Norton (water) 8000: 3u

This is a significant difference in particle size right?

I guess there is a followup question. The table you provided had a label at the top "American Standard (Grit)".
How "standard" is the American Standard? Is it one of those standards you can go to an independent certification company to get your product certified?
And then, are all/most hone companies using that standard? Internationally?

Originally Posted by Bruno

Hi guys, I deleted an insulting post, and asked the poster to simply not participate if he thinks a topic is boring, and not to belittle those who enjoy it.

I deleted the post because I don't want people (esp newbies) to feel discouraged from discussing every last minute detail of honing (or whatever else). If you wouldn't feel comfortable discussing those things here, then where else would you?


As you were. Have fun

Hey Guys, It was my post which was deleted, I would like to apologize for putting a negative spin, however unintentional, still not my place. My intent being irrelevant at this point, still I would like to extend my apologies, and grattitude to yall for being so helpfull regardless of one being a dumbass. Again I was wrong in the manner in which I posted, and for that I apologize.

Thanks,
Paul

You really can't compare a natural stone to a synthetic one. natural stones can have the cutting medium, say garnets of all different sizes and particle shapes. Hopefully what makes it a superior honing medium is that the particles are as uniform as your ever going to get them in a natural stone.Synthetic stones use manufactured particles so hopefully they are better sorted for uniformity. I know when you buy diamond compound what diferentiates the more expensive stuff from the cheaper stuff is the degree of sorting that goes on so the uniformity is higher in the better compound. Years ago I used to go mineral collecting at a garnet quarry in Connecticut and the rock had garnet xtls ranging from 1/16th of an inch up to a inch across and pieces of garnets in micron sizes. I don't think that rock would make a good honing stone.

Originally Posted by AFDavis11

I'm confused. I thought a 4K hone contained a substrate that held, generally, all 3 micron sized grit particles, and an 8K hone contained, generally, substrate that held 1 micron sized particles.

4,000 particles per square inch? Really?

I could easily be wrong, but if I understand it correctly, the grit system was originated by the abrasives industry long time ago. They use mesh screens to classify particle sizes. The biggest particles that pass the holes of the screen define the particular grit class. I was told this is reasonably accurate within the lower grits sandpapers, the mesh being defined in holes per square inch. Of course the mesh wires are also made out of something, so the holes must be smaller than the math in my initial post.

In the higher grit ranges, different manufacturers seem to use different size/grit ratios.
Some even may refer to the average particle size, while others use the largest particle size present.
All very confusing.

from ]http://www.supergrit.com

ABRASIVE GRIT SIZE COMPARISONS
There are three measurement systems for the size of abrasive grit: US CAMI (Coated Abrasives Manufacturers
Institute) or ANSI, European (FEPA Federation of European Producers Association), and Micron grading. CAMI
tolerates the most deviation of grit size for a specified grit. FEPAhas tighter tolerances. Micron is even tighter. Up
to 240 Grit, CAMI & FEPA grading is similar. As grits go finer, FEPA grit numbers go up faster than CAMI.
Example: FEPA 600P = CAMI 360, FEPA 1200P = CAMI 600. 20 MICRON corresponds to about 400 grit CAMI or
800P FEPA. The trend is to adopt the European FEPAgrading system even in the USA.


Going by the above, grit and mesh can be, and ARE, significantly different, depending which scale you use. The following excerpt from the next page.

http://www.supergrit.com/downloads/S...og05_page4.pdf


based on that, I think Bart is headed in the right direction. Possibly.

In the DMT system of grading, a Coarse stone is 45 microns and 325 "mesh equivalent". The Fine is 25 microns and 600 mesh equivalent. The Extra Extra Fine is 3 microns and 8000 mesh equivalent. Their ceramic stone is 7 microns and 2200 mesh equivalent. Their Gray Diamond compound is 1 micron and 15000 mesh equivalent.

I think some of the confusion in all of this is that there is a standard for artificial stones be they diamond or ceramic but for natural stones? Not so much. I've long maintained that I feel the Chinese stones, for instance, are misgraded. As some astute person mentioned in a previous post, it probably has a lot to do with marketing the hones and we all know how marketing goes!