More words of wisdom from Emory Kimbrough:
1) If you need to drill a lot of holes through metal, fill a soda bottle cap (or similar tiny little cup) with whatever cutting fluid you’re using as a lubricant and coolant. Position this just below the hole in your drill press table and adjust the press so that the tip of the drill bit will dip into the cup at the bottom of its travel. Now, every time you drill a hole, you’ll automatically be re-lubricating your bit.
2) If you don’t have one of the many commercial coolant/lubricant products on hand that are sold as cutting fluids or tapping fluids, then using 3-in-1 Oil, WD-40, baby oil, mineral/paraffin oil, or even cooking oil. They are all better than using no cutting fluid at all. Single-weight, non-detergent motor oil also works well, however, do not use multi-weight motor oils or oils with detergents and additives. Those can corrode copper, brass, and bronze – and even if you’re not drilling into those metals, that expensive power tool you’re using could have copper parts and wires inside.
3) You’ve been lied to! A ¼” round drill bit will not drill a ¼” round hole. The tip of the bit will wobble around a little, even if secured properly in a good drill press. Thus, the hole will be slightly larger than the size of the bit, and it won’t be exactly round. For woodworking, this tiny error is almost always too small to matter, but in metalworking, it can be important. For example, you may need a shaft to turn or slide very smoothly but without any play or vibration in a hole drilled in metal. For this, you need a reamer. This tool looks somewhat like a tap, with cutting edges on the side instead of the tip. To use it, first drill a hole just slightly smaller than the desired diameter, then follow that with the reamer, taking out just a wee bit more material to create a perfectly round hole of the exact desired diameter. Yes, you’ll want a drill press or a lathe for this, not a hand-held drill. An added benefit: the reamer will create a much smoother bore than a drill bit.