Machining plexiglass

To cut square holes in plexiglass.
Drill a hole smaller than your marked out square, use waste plexi as a back up, clamp it so it cant jump. Try not to drill all the way through the waste, this makes clean holes with no grabbing or breaks. Use a high drill speed. Fit a small piece of a fine square file to your jigsaw and go for it. Spray the swarf away with CRC (spray lube), and clean the file regularly. Don't push too hard and let the jigsaw do the work. Stick some tape to the shoe of the jigsaw so you don't scratch the plexi. It's a bit messy, but neat and quick. I've had good success with this method with minimal breakages.

Gwyn

Have considered using Lexan. Much more forgiving, if you scratch it, apply heat and the scratch goes away, and it's not brittle, even after heated it does not chip. Just another option.

Followed your advice and it worked just fine. Thanks so much for a good advice :D

Cheers Paul, good for you!

Gwyn

Thanks for the advice. I've got a LOT of square holes to drill in plexi and was wondering how I was going to do this. Excellent tip!

Steve