# Lock Miter Bits



## darenrogers (Jan 18, 2010)

I have some wall cabinets I need to make. I'm using 3/4" mahogany plywood and am trying to decide on the best method to join the four pieces together. I'm debating the effectiveness and quality of using a 45 degree lock miter router bit, allowing me to basically miter the corners together, but in a more stable and secure way.

Does anyone have any experience or recommendations on the following?

http://www.mlcswoodworking.com/shop...ges/bt_lockmiter.html#lock_miter_video_anchor

http://www.amanatool.com/bits-fv/55393.html

I've heard there is a tearout issue when running plywood vertically across these bits. Any thoughts anyone has are welcomed!


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## mdntrdr (Dec 22, 2009)

A simple rabbit or dado, top and bottom of sides, would be a better joint for plywood joining IMO.

Are theese cabinets going to have face frames?


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## darenrogers (Jan 18, 2010)

mdntrdr said:


> Are theese cabinets going to have face frames?


No face frames, frameless. I'm debating whether or not I want to see the plywood end grain at all, otherwise I would definitely go with a rabbit joint.


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## Gene Howe (Feb 28, 2009)

Get the set up doohicky!!!! Actually, Take a look at Freuds set up gauge. Very ingenious.
I have a Freud lock miter bit and it does offer some tear out on ply.
Two ways to minimize tear out: A back up board or, the way I do it is cut my piece a little over sized and rip it to size AFTER using the bit.


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## robertd (Jan 28, 2010)

Check out Sommerfeld tools. I say his cabinet making system at a woodworking show a few years back and bought it. It is a great easy to use system. I love it. I supplied a link so that you can check him out. 
http://www.sommerfeldtools.com/


Bob d


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## rrich (Jun 24, 2009)

There is a book, "In the craftsman style" and on page 131 (This is off the top of my head.) there are instructions for setting up to use a lock miter bit. These instructions work rather well.

In the plywood chip out issue, there was something about using a table saw at 45° and just barely cutting the surface to make the miter bit cut perfect. The saw blade is used to score the plywood before the mite bit cut. I've never tried it so YMMV.

However the suggestion of a rabbet joint seems to be the best solution. Make the rabbet very deep leaving only the final layer of the veneer to cover the edge of the joining plywood. There is enough surface area with good grain orientation in the edge of plywood to give a good strong joint.


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