That difference really confused me. I figured the P designation was a brand or quality thing until I looked into it. I printed out a chart and just wrote what was recommended at the different grits.

Quote Originally Posted by shogun View Post
What it shows is two colored sections, a section where the difference is small enough to not matter too much (green) and a section from where difference is huge and must be thought of (red). As can be seen, it is only when using finer grits that the difference need to be considered. But in the fine grits, the difference is huge.
http://www.mibnet.se/home-improvemen...standards.html