Best way to drill holes in plastic tailights ?

Hi , 

i want to drill  a hole in each of my tail lights to mount some back up / rear view cameras  on my van , 

the hole is about 19mm / 3/4 inch , 

What is the best way to do this and not crack the lens ?

Thanks for your ideas......

Go up in stages.  Maybe with a step drill?

use silicone glue to attach a washer, thoroughly tape off, and sandblast the hole.

Excessive, I know, but the question was for the best way to do it.

Step drill.

Go slow, you want to cut a hole, not melt one.

Dont push hard, let the drill bit do the work. 

Main thing is not to let the plastic get too hot. If you go too far with heat it'll fubar the whole project. 

Once you have a pilot hole, use a hole saw and spin the drill backwards.   That's how we cut the holes in fiberglass tub surrounds.  Spinning forward, the teeth of the saw can grab as it finishes the cut and crack off a huge chunk.  So, whenever you have to cut a hole in something that can crack, spin it backwards.  Same trick works on vinyl siding when its cold.  Mount the saw blade backwards to make your cuts and you won't shatter the siding.

I have used the step drills (Christmas Tree bit) to put holes in acrylic motorcycle windscreens to good effect. 

Matthew

uni-bit  single flute drill