I'm refinishing a stock on a Steyr Model S that had a really bad refinish in a prior life. Looked like shellac. I got a single 90 degree cutter to clean out the checkering after stripping and scrubbing. It seems that it is effecting only the top of the checkering and not getting to the bottom where where the groove is darker. Is it possible that the grooves are 60 degrees and I should consider a 60 deg cutter? Thanks for your ideas...Y