I've work with Al. in many alloys and the most important thing I've found is use a sharp tool, second feed and speeds.
If you use a bench top drill press it's hard to get the RPM's low enough not to create heat and vibration. I saw that locating punch and thought about getting one but didn't... yet!
also a pilot drill can help but if your using a mill for the barrel hole, the setup should be stiff enough that you don't need to step drill to the final size.
I would step drill if using a small or light duty drill press.
""Keep Smiling...It'll keep em guessing""
Last edited by mattmaxsr; 03-05-2012 at 11:10 AM..