Upcut vs. Downcut vs. Compression

[reals8gy]

Originally Posted by Kyle Stapleton

How are you holding this down?

I currently don't have vacuum, so the holes are drilled while the perimeter is either clamped or "through screwed." I look forward to the day of laying down the material and moving a valve handle.

[rcrawford]

Use a compression bit for both cuts. 1/4" works, but 3/8" is my favourite.

When cutting the 3/4" holes, use an inside profile cut with a spiral and an offset last pass (so it spirals down the profile just a little smaller than you need, and then gives one last profile cut around the edge to remove the little excess that was left). This give the fastest, cleanest holes.

I always find that upcut bits give me a rough top edge on MDF.