Roughing: Use the largest available corner radius unless otherwise specified.
Finish boring: Use the smallest available corner radius to minimize tool deflection.
Best finish: Generally start with your feed at 25% of insert nose radius. Optimal speeds and feeds depend upon material, tool overhang, and setup conditions.
P = steel, M = stainless, K = cast iron, S = refractory titanium
H = hardened material, N = aluminum & alloys