Routering sink cut out

JCorb | Posted in General Discussion on April 17, 2020 01:43pm

I am in the middle of a kitchen remodel, and we are installing Maple butcher block cabinets. I have basic woodworking skills, as I am an electrician by trade, but I do know my way around the wood shop. I am preparing to cut the sink (undermount) opening in my butcher block, but I am trying to find the best option for the least amount of tear out. I currently have the countertop sitting with bottom face up. I have laid out the sink on the bottom side with the template they provided, along with making my own template out of 3/4 sande plywood. I was planning on using an up cut spiral bit, with a bushing to get close to the finished size, but not sure if this is the right choice. I am wanting to save the sink cut out to make a cutting board, so I don’t want to lose size to straighten out the cuts. Hopefully this is all making sense to someone. But I guess my question is, has anyone done this? What tools did you use? What bits did you use for your router? And so on. There are quite a few questions really, I just have a wife who is my foreman when I am doing home projects, and I don’t need another lecture of why I am doing something wrong. Thank you in advance.

Replies

carbide_tipped | Apr 17, 2020 07:55pm | #1
If the countertop is 1 1/2 inch solid maple butcher block it's going to be a bit of a slog trying to do the cutout with only the router. You will have to make multiple passes going maybe 1/8 to 1/4 deeper each time. But it should give you a nice clean opening. Use a router with dust collection or have someone follow the cut with a shop vac to keep the cut clean. Make sure you support the cutout somehow so it doesn't drop and rip a chunk out as you get close to completing the cut. Best would be to set the whole thing on a sheet of scrap ply so the cutout is fully supported.

What I generally do, though, is cut the opening roughly 1/8-1/4 undersize and then clean it up with a router using a template. I use a good jigsaw to do the rough cut. With a thick, solid top, you have to cut very slowly so the blade doesn't stray from vertical. The ideal router bit for the cleanup would be a spiral compression bit with a bearing. The compression bit gives you a clean, tearout free cut on both surfaces because of it's design.

If you are comfortable doing a plunge cut with a circular saw, that's a faster way to do the straight parts of the rough cut, finishing the corners with the jigsaw.
mschlack | Apr 17, 2020 08:09pm | #2
I did this myself about 2 years ago for my daughter. She bought 8 ft sections of 1.5 inch oak butcher block from Lumber Liquidator. So I also made a template, but used thinner stock (1/2 inch) because that gives you more clearance below the template for the bit to cut. So I used a bearing on top bit, then flipped it over and used the same size but bearing on bottom bit to finish the cut. The technique worked fine -- there was no seam from the cuts coming from different sides.

I found I had to buy a new jigsaw. I wound up getting the Festool, which is amazingly powerful and cut through the oak easily to rough out the opening. That made it a lot easier.
gulfstar | Apr 17, 2020 09:00pm | #3
Did this a couple years ago in a one inch thick bar top with a 3/4 inch, double bearing trim bit.
JCorb | Apr 17, 2020 09:15pm | #4
With the compression spiral bit, there are many claims on what would be the best bit. There’s the mega flush double bearing, bottom bearing compression. What am I looking at for a cost so I know I am looking at the correct bit? The one I mentioned I saw on Infinity Cutting Tool and it’s roughly $70. Anyone heard of that bit?
carbide_tipped | Apr 20, 2020 10:17pm | #5
Infinity makes decent bits. Their 06-693 would be a good choice. Other good brands are whiteside, amana, freud, and CMT. Don't think you'll find a decent compression bit with bearings for much less than that $70.