You would need to place the metal over something to use as an anvil, and
then centre punch where you want to start drilling. Failing that, a U
shaped notch would probably do as well - couple of snips with string
side cutters, wiggle the tab created until it fatigues and falls off,
then file to final shape.
lamp to sit on, and have the cable exit throug that.


I was going to suggest a slot, but in my experience wiggling to fatigue
the tab is likely to distort the metal that its attached to.

Peter Scott