I tried to engrave text onto a flat surface using a 45 degree draft angle and could not figure out how to make it work.  Program wants a smaller draft angle, it works at 8° but not 9° though I can't detect why.  At that point only "most" of the cut has a flat bottom.

Since the text has variable width sections the depth at 45° winds up variable as well. 

Is there no way to cut at a 45° from a line on a flat surfact to a variable depth?

ADDED, file of part w text extrude cut through all.