Scribing a Farmhouse Sink to Fit

A heavy, irregularly-shaped sink needs to fit just right — the first time. The installer asks for help, and reports on his results. August 29, 2005

I am ready to install a ROHL Shaw's Original Fireclay farmhouse sink for the first time. The base cabinet has been set up perfectly by Crown Point, and there are extended stiles added to the front facing cutout to assure accuracy when installing. These sinks have 2" rounded corners on bottom front.

Since these sinks are handmade and have a +/- 2% from the original template, there is no official template supplied that I can use to draw the corner bottom front curves on my cabinet's stiles before cutting.

The sink is heavy - 112 lbs! I can't just set it on there to trace, plus it is huge and very awkward. Has anyone installed one of these sinks before? If so, what was your method of getting an accurate template onto the cabinet? I would want to just cut a 90 degree angle, and fill the curve in after with a small piece of wood that I could redo if I made mistakes, but, my client wants one seamless curved cutout. I have one chance at this. Also, what tool(s) did you use for cutting the curved corner cutouts? Any help is appreciated.

Forum Responses
(Cabinet and Millwork Installation Forum)
From contributor R:
I would suggest that you try laying the sink front or apron face down on a piece of cardboard on the floor and trace the perimeter onto the cardboard. Set the sink aside and determine the amount of overlap you need the sink to have to the cutout. Draw that outline inside the perimeter lines that you previously traced and then cutout the cardboard on the second (inside) line. Tape off the cabinet front and trace the cardboard pattern onto the cabinet front. Use a jigsaw to cut out the opening.

From contributor P:
I just finished a kitchen with one of these monster sinks. It was supposed to be an apron front (which is easier to build for and install) but the customer changed her mind (mid build) and purchased the farm sink.

Personally, I don't like the factory recommended install method of cutting and hoping it's right. What I'd do is cut the opening and then trim it out with a narrow molding. On the just finished install my installer tried to scribe the opening from a template like RWW suggests and missed. They had to caulk and fill (which to me looks awful) but the customer ok'd it rather than wait for me to make new stiles for the cab and hope they didn't miss again or use a trim molding.

For a one-shot attempt at perfection because the customer is demanding it, I'd show them the +/- variance issue and get them to sign off on it before cutting the cab face. This will give you some insurance against the gaps that will happen. Trace a pattern, cut the opening undersized and fit the sink with a hand rasp until it's perfect.
Forum Responses

From contributor A:
Who agreed to scribe a Shaw's farmhouse sink with the customer? Why? I had to save an install on one of these our designer spaced but had no clue how to deliver. We ended up having to order three total aprons in the end. I was never able to scribe the thing tight in the end. Caulk was used and looks like crap in my opinion. Keep in mind that this is sometimes a three-dimensional scribe if you use a 3/4" panel. To the best of my knowledge Shaw's doesn't show a picture in their ads of one of these with a tightly scribed apron. I'm curious as to why anyone with any knowledge of cabinetry and kitchens would attempt to sell one of these installs.

From the original questioner:
I managed to do it and did a pretty good job for the first time. I did use the cardboard cutout template idea that Contributor R recommended, and it worked out great.

This is what I did:
I laid the sink front flat onto the cardboard on the floor, but tracing the sink's contour was a challenge. The curves are so huge and dimensional from the front edge that I couldn't line up my pencil well. So instead I lined up my eye parallel to the sink side edges, and used Blue Painter's tape. This gave me a precise clean line on all the edges and I could easily pick it up and start again until I had it laid down just right.

To trace the curved corners I used a piece of thick card stock paper that was bendable, taped that to the sink and bent it around the corners, then drew the curves onto the cardboard. I cut out the cardboard template right on the line (knowing that this would be tight fit).

Before I drew my template onto the cabinet face, I slipped the cardboard template onto the front of the sink, just as if it was a stencil. Then I could really tell if it was a good fit or not before I made my cuts. I made slight adjustments to the template then slipped it on again for one final fit. When all was good, I taped the template in place onto the cabinet front and drew it out.

I used my hand circular saw with laser beam to cut the straight edges, and a jig for the curves. But the curves I cut inward from the line so I had room to sand to perfection with my drill bit sand drum. The drill bit sand drum worked out to be the lifesaver. I just kept placing the sink into the cutout position, could see where it needed sanding, pulled off the sink, sanded again, and again.

I think it took me about six tries, but when all was done, it gave me a pretty precise 1/16" fit and level. The good thing was that the sink's coating was tough and smooth, and it did not damage at all with all my reattempts to fitting into position.

From contributor M:
I see the original questioner was able to get everything to work and was very happy with the results. However, in his original post he had indicated that the sink was very heavy, huge and awkward to handle and maneuver.

If anybody has to do this in the future you might be able to take that cardboard template and transfer the pattern to a piece of 3/4" MDF. Take that piece of MDF and cut it and sand the cutout to fit exactly.

You will need to keep testing the fit of the MDF template around the sink instead of lifting the heavy awkward sink into a cabinet cutout to test fit. Once that MDF template is correctly adjusted and fit, take the MDF template and clamp it to the face of the cabinet. Then get a jigsaw and cut out the bulk of the material leaving about an 1/8" of material remaining. Then take your router with a top bearing and route out the remaining material to the template. Then all you need to do is run a piece of sandpaper, maybe 150-220 grit around the inside of the cutout do deburr and the sink is ready to drop into place for final fit. You only have to lift that heavy sink once (other than getting it into the kitchen).

From contributor B:
Well, after a little research, I found that fireclay expands .3 inches per 100 ft. per 100 degrees Fahrenheit temperature change. That’s only .01 in. for a 3-foot object, like a sink, which is not much.

On the other hand, when wood is exposed to moisture it can move a lot, as we well know. A moisture change from 12% to 18% will expand a typical wood board 36 in wide 1/2 to 7/8 inch across the grain. Allowing a 1/8" space for proper caulking with a good quality elastic caulk to keep water from the sink getting into the cut out skirt would be the right way to go.

The comments below were added after this Forum discussion was archived as a Knowledge Base article (add your comment).

Comment from contributor J:
What we did worked pretty well with minimal caulk. We jacked up the sink right in front of the cabinet so we could get a pretty good line for where to cut. We started by using a flat pencil and got a line to work from, then cut about .25 inside the line, then used a belt sander and tapered the cut to the inside. It took a couple of times picking that big beast up and putting it in the hole to get it looking right, but the finished product was pretty darn good. These farm sinks shed water down the face, also, so it is a good idea to keep that in mind if you have doors underneath - they will get wet and start to do wierd stuff.

Comment from contributor L:
Another option is to: Turn the sink upside down and mark where the cabinet will cope to the sink. Make a very rough, oversized cutout that will fit over the sink. Place said cutout over sink where the cabinet will scribe to it and use a compass to scribe the line to the template. Place template on a piece of MDF and transfer lines over. Cut out and make so it scribes to the sink, then rout the shape onto the cabinet.

Wood movement shouldn't be an issue as the rails that abut the sink are only a couple inches wide, not 36. Movement should be minimal. Still, there should be a very small and consistent gap that you can fill with silicone. If it's all consistent it should look good and be relatively water-tight.