Another interesting snippet (pg 11):

"The 600 and 200 grit wheels produced surfaces that were difficult to tell apart. In both cases the face abrasion marks were significantly larger and the edge burrs significantly wider and more convoluted than found with the 1000 grit wheels. In addition, the face view of the edges were significantly rougher and less straight than on the 1000 grit wheels. Nevertheless, the edges produced by the 600 and 200 girt wheels are quite thin, with a burr width on the order of 2 to 3 μm on the 600 wheels and 2 to 4 μm on the 200 wheels. And, from a practical point of view, the edges are quite sharp, being able to cut arm hair as well as the 1000 grit edges. Neither cut hair as easily, however, as a razor blade. This later fact is probably due in large part to the much smaller edge angle of the razor blades, 2β of 17o versus 40o."