I am installing a plastic project box at the pedestal to hold the mount for a new Ram mike. The box is about 1/8 in thick and I need to cut a 3/4 inch hole in it. I don't have any way to support the side of the box where I need to cut. Can anyone recommend the best way to make this hole without cracking the plastic? I have hole saws but am not sure they would work.

BTW, if anyone knows of a better mounting box than plastic please chime in! The dimensions I need are approx. 6 in long by 3in wide by 2 1/2 deep.
I plan to mount the box to the bottom of my Starboard binocular holder that clamps on to the pedestal guard.

Thanks !

Rodd