Lock Miter cutter-shaper

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Forum topic by unbob posted 07-16-2014 05:55 PM 1169 views 0 times favorited 5 replies Add to Favorites Watch
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810 posts in 2446 days

07-16-2014 05:55 PM

A friend working on his old house, needs to box in a pipe going through near center of a room. He is a good wood worker, and thinks the lock miter joint is what he wants for the long sides of the square column.
He will buy whatever cutter needed, cost not an issue.
There are many cutters out there, not tons of info.
One caught my eye, a single lock cutter that requires a second operation on a table saw, but seems to be preferred, and one of the more expensive ones.
The length of the column will be around 7ft, using local walnut.
I have a heavy shaper that has fine adjustments, would seem to be more able to do this then a router table.
Any thoughts on this?

5 replies so far

View RockyTopScott's profile


1186 posts in 4021 days

#1 posted 07-16-2014 06:03 PM

If the column will not take any abuse a simple miter would work and you could fix any gap issues with a block plane at the worksite. The glue will be enough.

-- “When you want to help people, you tell them the truth. When you want to help yourself, you tell them what they want to hear.” ― Thomas Sowell

View joeyinsouthaustin's profile


1294 posts in 2615 days

#2 posted 07-16-2014 07:32 PM

I do my Lock mitre’s on my 3hp powermatic shaper. I would use the shaper over the router table. Reg mitres will work, but IMO a properly set up locking mitre is faster and easier to assemble. Time wise it is a wash, and the quality and strength is better.

I use a bit that uses a flat cut on one piece and a standing cut on the other. Really like it. I use a powerfeed on the flat cut, and a custom feather board set up on the standing cut.

-- Who is John Galt?

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810 posts in 2446 days

#3 posted 07-16-2014 08:18 PM

He has a contractor doing some major work on the place. The contractor said that is how he would do it, and quoted a pretty high price. The piece will have to be assembled around the pipe. Seems the lock miter would make that easier. I wasn’t aware of this cutter or joint until this came up. My part of the deal, I get to keep the cutter-the cutter will need 1 1/4” bore for my shaper. Another CL by the seat of my pants deal.

View pintodeluxe's profile


6002 posts in 3356 days

#4 posted 07-16-2014 08:53 PM

I would go for it. A shaper or router table can handle a locking miter joint just fine. I recommend making the cuts in multiple passes. I use 1/4” plywood shims on my router table fence to make locking miters in 2 passes.
Be sure to cut both edges of a given board with the same profile. IE: cut both edges on one board referencing the shaper table, and both edges of the next board referencing the fence. That way you can assemble the parts with clamping pressure in only one direction.
I made the mistake of milling the edges the wrong way one time, and it made glueup a pain.
The locking miter is a great joint. If your stock is flat and true, the joint stick together before glue is even added!

-- Willie, Washington "If You Choose Not To Decide, You Still Have Made a Choice" - Rush

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810 posts in 2446 days

#5 posted 07-16-2014 10:10 PM

Thanks for the explanation pinto!
That makes a lot of sense.

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