cutting a 1 1/8" hole in plastic

[John B.]

A 1 1/8" spade bit is under $6 at Home Depot, Menards, Harbor Freight and will go through a 1/4" of plastic in seconds.

[apocketfulofwry]

Pro tip: If you decide to go the hole saw route, after carefully drilling the initial hole, run the drill in reverse to prevent cracking especially if the plastic is brittle.

[Fritz]

Spade bit. Forgot about them. On to Lowes

[Bernie]

I have everything mentioned.

Soldering iron and a file.

[Fritz]

be right there ...

[macphanatic]

If you go with a spade bit, go undersized and file it larger. A hole saw will make a clean cut. Spade bit in plastic may not and might very well chip or crack the plastic. The plastic in your car is old and might be brittle.

[Ken Sp.]

You could heat up a piece of metal tube the same size and use that to melt the hole.

[Bernie]

Ken Sp. wrote:
You could heat up a piece of metal tube the same size and use that to melt the hole.

:agree: