Here is some info about the specific sink I am looking at...

- Required outside cabinet: 33''
- Cutout Size: 32-1/4'' x 21-1/4''

*If undermount installation, the required cabinet space should be 35".

My Rachiele copper sink is 30" and is made to fit within a 30" cab, but obviously that doesn't translate to most sinks. You could keep your 33 cab and have a nice 30" single bowl sink, too.

There are people here that undermount a 33 in sink in a 33 in cabinet. I think the most recent thread about that was several weeks ago, so try searching via google (add site=ths.gardenweb to your search terms) vs the forum search feature.

I almost did this. This is what I learned here.
-do not cut down the sides to do this in frameless cabinets, pick a different sink
-the 33 in would be from edge to edge. You need to make sure the outside bowl wall to outside bowl wall measurement is less than 33 in (cabinet width) - 2xcabinet wall width.
-if you ever need to replace the sink, it will be difficult

It is done though, and there are people here that have posted about it. I ultimately decided to pick a different sink since I used frameless cabinets. I now have a Franke Orca and love it! It is huge, but only needs a 33 in cabinet (it's maybe 31 inches? Can't recall exactly).

I love my silgranit précis cascade, it fits in a 33" cabinet and the cutout (for a positive reveal) is 28 3/4 x 18 1/8"

Would your 21 1/4 depth sink fit well if you have standard depth counters? With room for a faucet? Would your fabricator seam at the sink? These things all worked out really well for me, which was partly dumb luck because I didn't know to ask about them when I was in the layout stage.

Here is a link that might be useful: precis cascade specs

williamsen, the bowl to bowl width is less than 33" and I do not have frameless cabinets. However, I will ask the stone fabricator and cabinet guy for their recommendations about this because I am a little concerned. I could still increase the cabinet size to a 36" but would rather not because this will effect the layout a little. I wonder if having clipped corners will cause additional problems??

kksmama, I was hoping to get the silgranit diamond 1 1/2 bowl. If it doesn't end up working out then the precis cascade looks to be a good alternative. Unless I increase the cabinet size...

Remember, the 33" is the outside dimension of the cabinet - assuming 3/4" walls, your inside dimension is 31-1/2". The sink flange can be wide than this, if it sits on top of the cabinet walls, but the bowls themselves need to be less than the inside cabinet dimension.

OTOH, I put this sink in a 30" base. I had custom cabinets built by a local shop, and I bought the sink before they started cutting lumber for my kitchen. My cabinet guy measured the sink, and assured me it would fit in the 30" base (if not, he would have added fractions of an inch to make it fit). Like you, I wanted to maximize every inch around the sink.

Here is a link that might be useful: Ann's sink

"Remember, the 33" is the outside dimension of the cabinet - assuming 3/4" walls, your inside dimension is 31-1/2". The sink flange can be wide than this, if it sits on top of the cabinet walls, but the bowls themselves need to be less than the inside cabinet dimension."

Respectfully, you can cut the sides of a framed or frameless cabinet to accommodate a larger sink. The only question are the adjacent cabinets. If they are upper drawers, you'll gain little; a dishwasher, you'll gain a bit more; a filler and you're good. The bowls do not need to be less than the inside cabinet dimension.

I've seen the results of "scooping" the cabinet sides and I NEVER recommend it. (When the cabinet doesn't provide good support, the counter cracks.) A heavy sink full of water needs all the support it can get. Remember it voids your warranty to do it, and that right there (plus the fact that you don't want it crashing down in the bottom of the cabinet) should be enough to push aside that idea.

When the sink manufacturer tells you to use a 36" base, use a 36" base.

Thank you all for your advice and expertise! It's very helpful to get lots of opinions before making decisions.

I presented this issue to my cabinet guy and my fabricator. Both assure me that this sink can, in fact, be installed into a 33" cabinet without compromising the strength of the counter or the cabinet. I sure hope they're right cuz I think I'm going to roll the dice and go with it. At this point my brain is mush from over thinking kitchen decisions anyway. I'm still perplexed (as I know nothing about it) why Blanco would say that it can be installed in a 33" cabinet if being top-mounted but needs a 35" cabinet if being undermounted when the sink itself, at the widest point, is only 32 1/2"...

Top mount only has to fit the bowls, the flanges sit on top of the counter to hold up the sink.

Undermount has to allow for the flanges to fit inside the cabinet and be clipped in place to support the sink.