My trick to cut a blade pickup switch slot on a back routed guitar body.

Many attempts but usually fail to get the Dremel to rout properly in a straight pass even using router base and guard rails.

Then the idea of punching holes along a pencilled line then drilling each hole through.  I followed the process with a Dremel router mounted on a base that runs along guard rails on each side. Clean up with a strip of sandpaper through the slot and it's done.