Here are some formulas machinist use
SFM= surface feet per minute. This depends on the type of cutter diameter of tool and type of material. I run between 150 and 200 on aluminum.
IPM= inches per minute feed rate
SFM=0.262 x dia of cutter x rpm
RPM= 3.82 x sfm / dia of cutter
use these formulas along with the recommended SFM above, a feed rate you are comfortable with and a RPM your machine can handle to get your speeds and feeds