Here is my problem:

I'm trying to engrave glass plate with my cnc router. I have a dremel 35,000 rpm and dremel engraving bit. When I start out the first letter--1.5 inch high, parkavenue font--turns out great. However, by the second letter the bit is "scratching the glass" not "frosting it".

Some things I tried:

1. Changed Z axis.
2. Tried different bits--dremel brand engraving.
3. Changed feed rate up and down.

Any hints or tips would be greatly appreaciated.

Matt