[John Gutmann]

I have machined delrin, ABS and PVC before and they all work great. I would have to say the easy thing to machine was the PVC. I don't remember the spindle or feed rate, but I do remember I cranked up the feed rate and I didn't even have to debur any edges. It was almost as easy as machining those wax blocks. Like everyone else is saying the material greatly depends on your application.

I have heard a ton of great things about Baltic Birch Plywood. I would say your best bet with that is to take off a few millimeters at a time with a larger bit and a fast feed. I would say you should have no problem using a 1/2" or 3/4" bit. Heck if you can find it a 1" bit should be fine. I have taken huge passes with a 3/4" bit through aluminum and never had a problem.

-John