I plan to install an undermount sink in a new butch block counter top that is 1 1/8" thick. In order to cut the sink hole, could I simply attach the undermount sink to the counter in the correct position, then use a router with a bottom bearing flush trim bit (1 1/4" carbide) to cut the sink, with the bearing running along the inside of the attached sink? I have read about the method of creating a template out of plywood, but this method seems like it would be easier and more accurate. Is there something I am not thinking about?

1 Answer 1


Putting a bearing against a sink surface seems to be looking for trouble. The slightest resistance in the bearing could tear up the finish of the sink, whether it is porcelain, fireclay, steel or resin.

I think it's worth the trouble to make a plywood template, unless you are in the sink business and have spare units to burn.

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    The other reasons for templates is that you can either allow more easily for the extra clearance required for the fit. Wood can shrink and grow by relatively large increments compared to the sink. Mar 10, 2015 at 18:08

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