How to precisely join PVC boards at 90º ?
I'm working on a frame for a mini CNC machine. It is made of 1/2" PVC sheet. The base is a square frame, it's 4" tall and 14" on each side. I'm trying to figure out the best way to join them very straight and secure.
I was thinking of using a butt joint, end drilling the shorter boards and threading the holes, or cutting a notch and putting a nut in it, and then just bolting the longer boards onto the sides, then adding a gusset where I have room. But I'm not sure how to get a true end drill hole in the end of a board. I have access to a drill press, but I can't find an explanation of the proper technique. If I clamp it by one of the small edges with the length sticking up I feel like it wouldn't be that secure.
Any other advice or ideas on how to join the PVC boards at 90 degrees is welcome. Thanks.