Best cnc bit for plywood, up-down bit, 2 or 3 flutes?

[LiamN (Liam Newcombe)]

Here’s a few tests of different cutters I did in baltic birch;

Baltic birch Plywood

So, I went and found some offcuts of furniture grade 18mm Baltic Birch Ply and did some experiments with some blunt cutters, sharp cutter and a compression cutter. The TLDR is that, if you use sensible feed rates, a good toolpath strategy and are prepared to do a little manual finishing, you can get away with surprisingly blunt upcut cutters. I found the fastest way to tell if the cutter was still sharp was to carefully and gently run my thumb across (not along) the cutting edge near the top …