WittyMonikerGoesHere t1_j24q0dz wrote on December 29, 2022 at 5:24 PM

Drilling a hole in the flange won't cause any structural issues in the sink, if that's what you're asking.

If it wasn't undermount, I'd recommend releasing the sink and popping the silicone, then putting a block between them to drill the first hole, but that's a much bigger deal to do with an undermount sink.

What you're suggesting is probably your best option, but understand that there's a good chance your diamond bit will be headed for the garbage as soon as it touches the steel.

If it's only a half inch hole, a hole saw may not be the best choice. I'd probably drill the steel stepping up to ½ with carbide drop points.

multimetier t1_j25ab4b wrote on December 29, 2022 at 7:34 PM

I would also use a drill bit for steel rather than the holesaw, but I wouldn't bother to step up the bits. Easier to just start with the desired size bit, as wear isn't issue with one hole thru sheetmetal. That lets you drill one hole and you're done.