Feed Rate, Plunge Rate, RPM

[RSP]

Hello I have PVC material and am trying to cut out letters. I have a onsrud 1/8" upspirle. Im only using this to cut the insides of "a" and clean up small ariaes where the 1/4" wont fit. Please advise as to Feed Rate, Plunge Rate, and RPMs, I am useing aspire if that make any difference. Thank you.

[RossMosh]

75-100ipm. 20-30ipm plunge. DOC = .125-.25. RPM ~ 13,000 RPM (two flute). 13-18,000 on an "O" Flute.

I've found slower, with more aggressive depths work best. Varying RPM hasn't made a significant difference on cut quality but you want to bump the RPM on an "O" flute bit. If bumping the RPM causes issues, then slow down the machine a bit.