Plexiglass is a great substitute for glass, but it has one limitation. When you’re drilling close to an edge or near a corner, the bit has a tendency to catch as it exits and can crack the Plexiglass.
Here’s a tip to prevent that: Sandwich the Plexiglass between two layers of 1/4-inch plywood. Mark your holes on the plywood and drill through all three layers.
Watch the video for details.