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sink and flush trim bit

Posted by poorowner (My Page) on
Wed, Jan 28, 09 at 21:53

I have this idea, I am going to cut the butcher block counter close enough and use a 2" long flush trim bottom bearing router bit and the ACTUAL undermount SINK as a template, I can route the exact shape that fits perfectly (zero reveal)

I have to be very careful not to go too low and touch the sink, of course.

Is it possible to do a slight positive reveal from there?

Follow-Up Postings:

RE: sink and flush trim bit

I recommend 1/4" masonite, smooth both sides, for making a template. Trace the sink onto the masonite and cut it out with your jigsaw. Add some strongbacks under the template on either side of the cutout, and clamp to them so the template will not sag in the middle.

That 2" long flush trim bottom bearing router bit cost over $100, right? Don't use a cheap one of those- make sure it is from a good manufacturer. I will not use router bits if they were made in China. Inferior metal and poorly braised cutting tips can lead to a deadly projectile. I bought a new dovetail bit last year and the only one left at the store was a cheap one. I needed it for the thing I was working on, so i bought it anyway. It lost both the cutting tips as soon as it touched wood! That was a risk I didn't need to take.

Quality router bit

This is a good one. The spiral cutter is pretty much necessary to avoid tear-out in Maple. Down cut means the top edge will be the clean side of the cut.

Here is a link that might be useful: 1/2

RE: sink and flush trim bit

Ok, thanks, that's alot of money for the job. so far I have bought freud and they are made in Italy, the regular 2" long bit is $15 no bearing and with bearing is $28, it's not spiral but it will have to do I guess.

For other stuff I bought a set of craftsman for $100 and it has all kinds of 1/4" shank bits, those are doing fine on particle boards.

RE: sink and flush trim bit

Freud is a good manufacturer. The cheapest domestic manufacturer I know of is Woodline. They are made here in the US, in Arizona, I believe.

I urge you to get a spiral cutting bit. Maple is really prone to tear-out when the grain changes direction. If you have scraps of the butcher block please practice on them first. I don't want your countertop to get ruined, I know how long you have been working on it.

The bearing is not necessary. A guide bushing mounted to the base of your router, tracing a template clamped to the top side of your workpiece, does the same thing. I use the spiral cutters without a bearing because I also am too cheap to spend that much on a router bit.

Particle board is a different animal from real wood. Tear-out occurs when the grain splits and extra material is removed from the workpiece. It is just like a really large splinter coming off the surface. The curved cutting edge of the spiral bit shaves the grain at an angle so it can't splinter. Since there is no grain in particle board, this is not an issue.

RE: sink and flush trim bit

Thanks for your advice.. Looks like maybe I am going to get a spiral no bearing bit for all cutting. So maybe a whiteside spiral or rockler, or something not made in china as this will my main bit for the whole fabication job. Maybe use my cheapy bearing bits to fab a template with plywood or hardboard.

Besides the cut outs I have to do is it feasable to clean up the end grain edge with a router after I cut it with a circular saw?

RE: sink and flush trim bit

Yes, you are onthe right track. Cut the workpiece close to the desired size with a saw, circular or jig. Stay about 1/8 to 1/4" back from where you want the finish cut to be made. Use the router to clean it up. The router can remove the rest in a single pass. If you wanted to use the router for the complete cut-out it would have to be done gradually in several passes, each time plunging the bit a little deeper.

RE: sink and flush trim bit

There are even combined upshear/downshear bits if you need both the top and bottom surfaces to be good.

The shaft half of the cutter is down shear to avoid pull up damage on the top, while the other half of the cutter is up shear to produce a clean bottom surface.

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