Quote Originally Posted by Ben325e View Post
The problem with this is that you seem to be associating particle size with depth/size of cut. Just because something has larger particles does NOT mean that it cuts deeper than something with smaller particles. Particle hardness and particle shape play an important role. A (relatively larger) softer material with rounded edges has the potential to cut less than a smaller harder material with jagged edges.

Buying .3 micron Chromium Oxide sounds good, but what is more important is the tolerance to which the chromium oxide is held. If the tolerance is loose, then you can have (just theoretically speaking here) particles of over 1 micron in the mix, with about 80% of particles .3 micron or smaller. But if ~10% of the particles are in the 1 micron range, then that's what the end product is going to seem like.

Look at a strop loaded with chromium oxide. Now think about how many particles are on there. Imagine that 1 out of 10 particles are 1 micron and all the rest are .3 micron. When you drag a razor over that surface, the 1 micron particles are going to have a profound effect on the end result, much more so than the .3.

The short version: A .5 micron product held to tighter tolerances can be much better than a .3 micron product of loose tolerance.

I'm not saying that your .3 stuff is bad, it could be phenomenal. I'd just look at the purity and tolerance.


Another thing that we haven't even really gotten into is how different manufacturers measure and filter particles. We *think* we're comparing apples to apples but there's no guarantee.

Some companies use the JIS, but but others like Shapton use their own idiosyncratic sizing/grit relationships to come up with a number to stamp on their product.

Here is an edge I finished using that big green "crayon" brick chrome Oxide (before I had purchased ChrisL's real cromox...). That crayon is well known as having many different particle sizes. From 0.5 up to 3 or 6 micron. Sounds pretty rough, doesn't it?

Here's the result though:

500x




200x


That's a pretty smooth edge (Dovo Renaissance stainless). I used a hanging cavas strop.