I'm replacing the small cup holders with jumbo's in my dash. What is the best way to trim out about 1/4" around the hole? I've bought a carbide cutting bit for my drimmel. any input would be great!!!

yup, thats about the best way.if you wanted to use a hole saw you can bond a small piece of plywood over the back of the hole and use that to center the drill.

I used one of those rotozip cutters in my dremel. Worked really well. I got maybe 6 rectangular switches out of the bit before it burned up.

You could also try fitting two hole saws inside of each other.

Place a STRONG vacuum (hose) under the area you are cutting, and turn it on when cutting. It will aide you in clean-up. Rotozip tool works very well for this.

Just go slow and easy. I did 3 in my boat 2 weeks ago with a dremel. It wants to wander on you if you push to fast.

I used a coarse sandpaper flap wheel about 1 1/2" in dia. I put it in a die grinder and it cut the glass very nicely. Definitely use a vacuum. Just use a marker to scribe a line and sand to it.

I always put masking tape over the area to be cut and draw cut line with a contractors pencil. Bear in mind that the melted fiberglass from the rotozip will be hot and can melt vinyl so protect things around the cut.