I needed to drill a couple of 1″ holes in the stainless steel kitchen sink to install a pair of soap and lotion dispensers.
The most popular answer online was “use a bi-metal hole saw, low speed, lots of pressure, lots of lubricant.” I tried that, and the pilot bit wouldn’t even scratch it.
I happened to have a hammer drill and some 3/8″ bits, and those went through … eventually. So I tried to enlarge it with a 1″ hammer drill bit. I got a jagged hole and a burned out hammer drill motor, which I have to ship off for repair now, having used it only three times.
The next most popular answer seemed to be a conduit knockout punch, but that requires a pilot hole of 3/4″ (if I could make that, I wouldn’t need this punch, now would I?) and Lowe’s only carries them in a set of 4 for $150.
Fortunately, the manager appeared and talked me down to a $55 Greenlee step bit. Went home, popped it in my little “backup” drill, and had two nice clean holes in well under ten minutes.
Some tips:
– I bought a Greenlee step drill bit, $55 at Lowe’s. They also had an Irwin for $53, but the manager said the Greenlee is twice the quality of the Irwin.
– Measure the hole location every which way you can (remember, you only get one shot at this!), and then make a little starter divot with a hammer and nail or punch so the drill doesn’t wander over the surface.
– Don’t run the drill at full speed; you will work-harden the sink and dull the bit. If it’s smoking, you were going too fast.
– Don’t run the drill too slow. Apply firm downward pressure (we’re talking “both hands on the drill” firm, not “the combined body weight of you and your cousin Earl” firm.) If you run it too slow or don’t press firmly, when you finish one step and drop to the next step, it will gouge two chunks out of the side of the hole and lock the bit in place.
– Use plenty of lubricant. WD-40 is fine; any oil ought to suffice. Spray it on liberally before and during drilling.
– Don’t forget to mark on the drill bit where to stop – wrap a piece of masking tape around it at the right height, or you may get to repeat this procedure on a new sink.
