[HardcoreZ28]

Two other notes that just crossed my mind.

Be careful of your drill speed....keeping your speed low will keep the heat down and keep you from killing the bit. Even at a slow speed each weld seems to take less than 10 seconds to cut.

And to keep from cutting through both panels watch for a small puff of rusty smoke as you're drilling. This usually indicates that you've passed through the first panel.