First Oramask Plywood Cut

[LiamN (Liam Newcombe)]

Here’s an old thread with some discussion of some of the issues with plywood surface finish, upcut vs. downcut, roughing & finishing passes etc.

Baltic birch Plywood

Should I be using Up or down cut end mills to prevent tear out on the top of my baltic birch project? I have read using down cut ones will help, wondering your opinions. I ran a test with 1/8 endmills I have (not sure up or down) with a inner 3.8" diameter pocket .100 deep then a 4" outer cut through, leaving a lip that had tear out on top. Any opinions to stop the tear out?