Pre-drill round holes in the corners of your square hole. That way,
any cracking will stop at the corners.



That's what I ended up doing to the hard, brittle, faceplate I was
using. Drilled the holes veeeerrrry slowly, with no resulting problems.
Then I used my fine toothed coping saw to cut out the square hole for the
Anderson Powerpole chassis mount jacks. Also put a BNC antenna jack on the
plate. The whole thing will be my HF radio power and antenna connection in
my motorhome. It is now done, looks nice, and should be very functional.

My thanks to all who replied on this subject.

Ed K7AAT