I would like to make a gauge cluster for my car out of 1/4" thick wood, plastic, or plexiglass, it will be wrapped in carbon fiber vinyl when finished. Should I use a 3 3/8" hole-saw for a 3 3/8" gauge or should I use a smaller hole-saw and file it? The tachometer is 3 3/8" and my other gauges are 2 1/16".

I'm not using metal or aluminum simply because I don't have any tools to cut nice circles in them.
There are companies that make nice housings but they are way out of my price range(photo attached).

A good quality hole saw for metal will give you good results if you would prefer a metal panel. I would mount the panel to some 3/4" plywood as a backing before I drilled the holes so the panel doesn't deflect and distort the holes while drilling. Use the 3 3/8 and 2 1/16. Drill press recommended no matter what material you choose.

Kevin

Thanks, sounds easy enough.

I just spent 2 days making mine and now you post that lol, those are nice! Pretty affordable and you can arrange the gauges however you want them.

Nice, might have to pick one up.