flute count is important too. Especially for plastics a 2 flute is better since it gives more room for the material to escape. (correct me if I'm wrong, I'm not an expert!)
Also, make sure the cutting length of the bit is long enough to fit all the way through the material you're cutting. I bought a 1/8 bit with 1/4 shank only to find that it can't 'poke' through the wood before the 'neck' of the bit hits the surface. I now use a 1/8 bit and 1/4 adapter bushing. |