Quote Originally Posted by nova_robotics View Post
Could be, but the chips look like aluminum to me. Pushing a mill that hard with no coolant will cause steel chips to come off golden, blue or even red hot. Aluminum stays silver in appearance. It's a bit hard to judge scale, but to me that looks like a 1/2" - 3/4" end mill. That depth of cut and that speed would be very high for steel.

Edit: Yeah nevermind I think it's steel.
If it is steel then it is probably 12 or 14L