A couple thoughts regarding the current conversation:
In assessing abrasives you must be diligent in understanding if they are reported in grit, grain, mesh, sieve, etc. Some reporting methods are similar, some are not.
Another set of concepts is "break in" and "break out". Some (many) mediums will start out a bit more abrasive and inconsistent prior to break in. Over time they behave more consistently, give more uniform results, and generally behave like a finer abrasive.
Some people try to speed results by using more pressure. This is a really bad idea for some mediums as it induces "break out" where abrasives leave the surface and start rolling around and randomly gouging your work (the damage to the media is obvious, but it also damages your results). Obviously using stones that form a slurry are supposed to do this...this illustrates one difference between media types dealing with angularity.
Another point is that the chart should be used as an approximation since the data in the columns is not all from that same source. If you stay in a column, you will be OK, but when you start comparing manufacturers you are going to have a bit of difficulty since (presumably) the testing methods are not consistent for all manufactures. One GLARING example of inconsistency is the Spyderco uf media which is reported as 7 micron on this chart. It tends to polish as good or better than the DMT EEF (3 micron).
There is a whole other discussion regarding testing of edge holding relative to the media used to produce the edge. There are some surprising reports out there, and since my findings are pretty subjective at this point, I will keep them to myself. There are some people out there that spend a LOT of time working with this stuff.
Last edited by unit; 09-30-2010 at 08:12 AM.
Ken (my real name)
...learning something new all the time.