Cutting a 2" , 2.5" hole for instrument cluster

[caliber60]

What's the best way to cut 2" and 2.5" hole on a metal or aluminum panel? I have a lathe and thinking about a fly cutter. I know there are knockout punch can do the job as well. Any other suggestion?

[bell]

if you're dealing with a solid panel then you can't compete with a hole saw......

[david.avery]

If your using a bimetal saw, go get a brandy-new-one as the one you used to drill 3000 holes already will eat your aluminum for lunch.

I made a nice custom stepped holder once with a sheet metal brake, and then drilled the holes. The saw wandered and made a jagged nasty hole.

I finally settled on making a jig, which consisted of two 2*4's already drilled out, with my metal in the middle.

I would prefer to use my new toy, an air body saw. You can carve metal like butter with this. Practice a little, and you can write your name on the side of someone's car

The other idea is the mother of all uni-bits, I think they make a whopper, would probably cost lots of money, but the two smaller unibits I have work great.

-DMA