What type of dremel bit to use?

What type of bit would I need to modify a aluminum jig mold?

I would use a small file. Aluminum grinding with the bits in a drimmel kits are not a good combo.

I use one with a small diamond head. I got it from a dentist, but I think Dremel makes a similar head. It cuts the aluminum like butter. You need to keep a steady hand and take your time. I've also seen guys use a drill press to modify these molds. Look on www.advancedangler.com under the Randy Howell videos and you'll find some info on the drill press method. I don't have a drill press so I use the Dremel. It works fine.

http://www.amazon.com/Dremel-220-01-Rotary-Tool-Station/dp/B00068P48O