I would confirm it with the countertop people now before it's too late to change. Drilling stainless isn't nothing, but maybe they do it all the time.

The countertop installer won't be drilling it. They will cut the holes in the countertop but our GC said his plumber will drill through the holes from the countertop. I double check with our GC to see if they should drill it before the sink is installed and he said they are confident they can do it afterward.

I am sorry but I don't quite get your comment "And you will not be able to see the sink beneath the countertop". Can you clarify? I wouldn't I be able to see the sink? We are talking about additional holes in the sink for because the sink has a wide rim being a dual mount sink...of course the countertop will have the cut out for the sink...

Bump

I would be a little skeptical, too.

I guess if the GC is taking on all the responsibility for it (as he should), then it should be fine because he'll have to fix it if he damages it.

I would not be worried about the sink looking bad. I would worry about it getting bent or having its attachment to the counter compromised by the drill pressure (I assume the counter installers are attaching the sink?). Maybe the plumber does it all the time...

We have drilled hundreds of holes in countertops and sinks. A diamond-tipped bit is used for stone and estone; a lubricated steel bit is used to drill stainless steel. The diamond bit isn't going to drill the stainless steel, trust me.

We've had this problem and had to unmount the freshly-mounted undermount sink in order to drill the stainless steel after diamond bit marked the location of the new hole.

The stone fabricator needs to drill the top holes. The sink is temporarily clamped in place and the holes marked on the sink flange. The sink is unclamped and drilled, then strapped in place.

"Our GC said they will install the sink and countertop person will cut countertop with the additional holes and then they will drill from the top once everything is installed."

Nu-uh.

The bit for the stainless steel won't fit into the 1 3/8" hole cut by the diamond.

Hi Joseph,

Can you help me understand why a 1-3/8" steel bit wont fit through the 1-3/8" hole in the quartz countertop? Is it better to mark the holes and drill the sink and use that as a template to cut the countertop instead? The countertop people was a little worry about that approach because it would be hard to align all the holes with the countertop. He suggested drilling a bigger hole then needed (1 1/2) in the sink first if we decide to go that route.

I have read many posts by you and appreciate your expertise in this matter.

Thank you.

What about trimming off the sink deck ahead of installation? No holes to align that way...

Diamond blade in a grinder and rip off most of the sink flange ^.

"Can you help me understand why a 1-3/8" steel bit wont fit through the 1-3/8" hole in the quartz countertop?"

No, but mine won't. There may be some that do; I haven't found it.

"Is it better to mark the holes and drill the sink and use that as a template to cut the countertop instead?"

No.

"The countertop people was a little worry about that approach because it would be hard to align all the holes with the countertop. He suggested drilling a bigger hole then needed (1 1/2) in the sink first if we decide to go that route."

That'll work great until your water dispenser escutcheon only covers a 1 3/8" hole.

Thank you @Joseph Corlett, LLC.

@Fori, I like your idea! I am going to investigate metal fabricators nearby to see if someone can help me cut off the excess rim lip from the sink.

This bit will fit in an existing 1 3/8" countertop hole and drill an 1 3/8" hole in the SS beneath.

Terrible info in this thread.

Bwahhaaaaa. Stainless steel will laugh at that junk. Talk about terrible info. You need one of these.

I found a stainless steel metal fabrication shop that said they can trim off the excess sink lip/deck for $110. My GC would be charging $100 to drill the additional 4 holes that I need otherwise. Taking this into account, I am debating whether I should just get a different sink to save me the trouble. I found this one here that would meet my need (offset drain, slight radius corners, 9" deep, ~30" single bowl): https://www.amazon.com/DELTA-95B932-32S-SS-Workstation-Undermount-Accessories/dp/B0921BFT65. I don't really need a workstation sink with all these accessories but heck why not? After all is said and done, the Blanco with a grid would be 40% more expensive then the Delta.

@Joseph Corlett, LLC, I found another post where you recommended this very Blanco sink that I am having a dilemma over. Do you think the quality of the Blanco sink is worth the trouble & cost vs the Delta one that I found? I believe the Delta one is actually made by Kraus as Kraus was acquired by Delta last year.

Thanks