I'm having a bit of a problem peck milling. I've had recent success with some relatively larger hole. This time around, I'm drilling down .375" into a .0555 diameter piece of polycarbonate with a .031" drill (of high quality). I'm using the longer retract method. The hole comes through okay (the fixturing is a bear) but the inside walls seem to have a spiral cut into them looking a lot like the spiral of the drill bit (but probably just an artifact of whatever is not right).
Any suggestions are appreciated. I read some where this might be an anomaly of not enough dwell at the end of a peck and then rapid-ing above the last height.-Keith