Yes you can get through the quartz with a diamond/carbide grit hole saw. Then just buy a bi-metal hole saw to get through the stainless. The Milwaukee hole saws are home depot are good for ~20 holes in 18 gauge stainless. The trick is to not let the stainless get too hot and work harden. Use the lower speed on your drill, medium pressure, and spray some WD40 onto the metal as you're cutting. DO NOT CHEAP OUT ON THE HOLE SAW with a harbor freight or some other janky brand.
It sounds like you have an undermounted sink right? Make sure you don't put too much pressure on the flange then, so it doesn't buckle under the pressure of your drill.
cobymoby t1_j25qzyz wrote
Reply to Help drilling a hole through kitchen countertop & flange of undermount sink for a water filter by [deleted]
You're over thinking this a bit.
Yes you can get through the quartz with a diamond/carbide grit hole saw. Then just buy a bi-metal hole saw to get through the stainless. The Milwaukee hole saws are home depot are good for ~20 holes in 18 gauge stainless. The trick is to not let the stainless get too hot and work harden. Use the lower speed on your drill, medium pressure, and spray some WD40 onto the metal as you're cutting. DO NOT CHEAP OUT ON THE HOLE SAW with a harbor freight or some other janky brand.
It sounds like you have an undermounted sink right? Make sure you don't put too much pressure on the flange then, so it doesn't buckle under the pressure of your drill.
You got this!!