Upcut vs downcut tooling

[ScottsdaleSteve (Steve)]

Here’s a pic of the flute direction on up vs. down bits/endmills:

Also discussed in this thread:

Upcut vs. Downcut

How can you tell if a bit is Up Cut vs. Down Cut? I never paid much attention to my bits before. If they were up cut or down cut I cut a lot of my designs on PVC. When using a 1/4 or 1/8 inch bit the cut areas clear out pretty well. But when i use a 1/16 bit the cut area seems to clog up with the cuttings and i have to dig it out. Guess its time to check my bits and see if they are up or down cut Anyone have any experience with this.