Rob Wallace
A few additional resources that might help:

http://www.woodbin.com/misc/sandpaper_grit_chart.htm

http://www.fingerlakeswoodturners.com/downloads/Sand%20Paper%20Grit%20Comparison.pdf

http://www.uama.org/AbrasiveGrains101.html

There is lots of information on the similarities and differences of teh CAMI versus FEPA grading scales available in the Internet. Google is your friend.

Rob