No, the lip doesn't rest on top of the sides of your cabinet. It gets attached to either plywood supports that go across the top of your base cabinet, or to the countertop itself. It needs to fit WITHIN the dimensions of your cabinet, and it helps to have a little bit of wiggle/access room to attach it.

The sink has to have room to be physically attached to the top. That room is measured from the widest point. Interior bowl size is irrelevant to the rim size for attachment purposes.

Can someone draw a picture of this process? I often wondered about this myself during my remodel. My sink base has 25.5" on interior and I could never figure out why a 25" sink (exterior) wouldn't work. The cabs are solid on top if that means anything.

The manufacturers are allowing enough room for the use of the clips to attach the sink to the counter.

There have been posters on here who did use the sides of the cabinet for support, they had to cut down the sides where the sink lip rests so that the top of the sink is level with the top of the cabinet. Some of them said that their installers had much experience doing so. That is how they squeak a larger sink into the smallest possible cabinet. I make no claims as to the wisdom or lack of in this approach. However, I don't believe that I have ever seen anyone come back and say it proved to be a bad idea.

"I don't believe that I have ever seen anyone come back and say it proved to be a bad idea."

You may have missed the (several) posts where people had damaged or defective sinks that could not now be removed easily because the cabinet sides were scooped. They had to cut much larger holes in the cabinet sides to reach the clips, or in some cases, deconstruct the base and completely rebuild it.

Going smaller with a sink base than the sink manufacturer recommends is not ever a "best practice".

I faced a similar dilemma. Replacing our existing granite countertops/sink with granite and sink more of our liking I originally had my heart set on a specific Blanco sink and when I did my final measurement (thankfully) before ordering, I found out our cabinet was too small per the Blanco specs. I did not want to mess with the cabinet to make something fit against the manufacturer specs. Good news was that since I wanted to stay with a Blanco sink, it pushed me to look at a model I had not previously considered: BLANCO PRECIS⢠Cascade Super Single Bowl with a cabinet requirement of 33". Now I am very excited for my upcoming new sink installation to replace my current Kohler (double equal size) sink. I will gain the larger single bowl, but still keep some of the functionality of a second "bowl" with the included colander. Plus I will now have a single drain vs. current two, thus gaining some real estate under the sink where it is currently very cramped. Not sure if this model is to your liking (it does have a shallower bowl) or will offer you what you are looking for? Blanco doesn't - yet - make a sink grid for this model. They told our plumbing distributor that is has been frequently requested though, so they are considering one for next year. Good luck!

I am someone who eased the edges of a prep sink cabinet to the depth of the sink flange to install a sink in a smaller cabinet than specified by Blanco. They are playing it safe.

It was a trade off and I accepted the risks. The counter folks need to be dead on with templating and installation and in my case they were. It was a great choice for me and 10 years later, no problems.
You need to know exactly how it is going to be installed and your counter company needs to be on board.

Thanks for all the responses. I guess I don't understand how the clips get installed. The diagram on the blanco site isn't clear to me.

Judeny, it sounds like you didn't use the clips, right? You just mortised the top of the countertop base so that the top of the sink flange sits flush with the top of the countertop base?

My counter sits directly on the cabinets. They are 3/4" plywood boxes but I'm not sure that makes a difference. But yes, the sink flange is flush with sides of the cabinet.

It is a Blanco rondo prep sink and I have it in an 18" wide cabinet, so not a huge sink but other folks did scoop the sides of cabinets to fit a full size sink and I believe they did use clips.

As a complication, the sink base is the last cabinet on an island followed by an overhang so the cabinet could not be eased the full 3/4" thickness of the ply or it would show under the overhang. OK, probably no one would notice, but I would - the installer incrementally eased the cabinet side so it did not go through to the finished exposed side of the cabinet.

"It seems like my cabinet will work with this sink, right?"

Riley:

Yes. The sink can be clipped to the countertop before the top is installed, or your fabricator can install a Hercules Universal Sink Harness which makes access to clips irrelevant.

"Too small" sinks are often installed successfully. To understand the process in detail you could look at the photos in this thread - it's one way of doing it at least:
http://www.ikeafans.com/forums/kitchen-planning/51235-sink-too-big.html

We are planning to do the same. We did use a RTA sink cabinet but honestly because of the cutting and reinforcing we might as well have started with lumber. We used a sink setter but there are other good methods of attaching sinks other than clips.

In our case, my kitchen sink was going to have to fit in a 24" cabinet because it was the only way I could fit a fridge, dishwasher, sink, and corner cabinet on the tiny wall where they had to go. My previous corner cabinet was basically unusable. I ended up with a 25" undermount sink and I'm really pleased with this solution. I am using the sink in a temporary install so I am not worried about it being defective.

I did something similar with a Blanco Rondo. I misread the spec sheet and thought it would fix it in an 18" cabinet. Turns out that is drop in mount. That wasn't happening so we notched the walls of the cabinet so the sink would sit flush with the adjoining cabinet and panel. It worked for us. We didn't use any clips. Even the main sink is supported by 2x4s and not clips.