You can also buy dedicated spot-weld cutters for your drill. These incorporate a spring-loaded center point that anchors the bit-the teeth on the perimeter of the bit actually do the cutting. Villarroel recommended using something to lubricate the tip, whether you use a spot-weld cutter or a regular drill bit. He used gear lube, but you can also use WD-40. This keeps the bit from overheating and going dull. Don't push down too hard, either. That also causes excess heat that will dull your bit.