ran some tests today on mdf. i thought that a 20 degree bit would be good for the car, and the lettering. the car was ok, but the lettering went deeper than i thought it would. so, i ran another test (the one at the top is where the text will be), using a 30 degree bit. worked out pretty good, but a bit shallower than i would like. so, set it up so that the start depth was .01", and it worked out the best of the three tests. now to try this on real wood.