Drilling plastics or plexiglass

[bwoodburn]

I am trying to drill clean 5/8" dia. holes in plexiglass. Can anyone help me with how I might do this without cracking, melting or otherwise marring the material. The plexiglass is about 7/32'' thk.

[Will Call]

Clamp it between two pieces of 3/4 in pine and feed the drill slowly.

[j sleepingquail]

Thats a good idea but all you really need is the backup piece and be sure to use soapy water as a coolant (dish detergent and water) this improves the finish. If the hole is more than a diameter (5/8) deep then you should continually back off your feed to clear the hole. If it is a hand drill press then just lift the drill out to clear. You can use regular flat spade drills if they are sharp but i usually have to slightly relieve the sides so it doesn't bind in the hole.
good luck