Lock Miter Bit opinions, good/bad?

[blackhawk]

I've been woodworking for almost 30 years but I have never tried a lock miter bit. A friend wants me to build a shadow box to hang on the wall. I thought that it might be time to try out a lock miter joint for the corners. They are fairly pricey, starting out around $75. What is the general consensus on the lock miter? Do they work well and make a strong joint?

This shadow box will be 6" deep and some of the items sitting in it will have a little weight. So, I do need a strong joint.

 

[NCGrimbo]

I've got two of them. One if for wood up to 3/4" thick and the other one can handle up to 1 1/8". I've not thought about how much weight they can support since I used them in a joint that was vertical, not like your proposed horizontal joint. The joint has a lot more surface area than a regular miter joint, so i would suspect it to be stronger. One suggestion is to get a Lock Miter Jig. it makes setting up the cuts a lot easier, but not 100% fool proof. So have several pieces of scrap milled to the same size to make sure the router is set correctly before cutting the final joints.

 

[Jeff]

This shadow box will be 6" deep and some of the items sitting in it will have a little weight. So, I do need a strong joint.

You could use a simple miter joint with 2 cross grain splines at each corner which is also a strong miter joint. Much cheaper and less fussy to set up than a locked miter joint.

 

[PeteM]

IMO - Way too fussy to set up for occasional use. If you were making a bunch of the same item it might be worth it but for one or two items I don't think it's worth the time. As Jeff said, a miter joint with splines would be my choice.

 

[Rwe2156]

I agree with Pete - too fiddly for me to use/lots of other options

 

[Cuprousworks]

Agree, much better in theory than practice. Too much time and frustration, even with the set-up jig.
Mike

 

[Roy G]

My personal solution would be to dovetail the box, with the visible edge mitered. If I make a chest of drawers I make the base this way-not that hard and gives you good dovetail practice.

Roy G

 

[Pop Golden]

I have one I bought several years ago. Never figured out to make it work. I decided that as others in this post have said WAY TOO MUCH TROUBLE. Mine is for sale if one of you folks out there wants to fiddle with it. $25.00 and it's yours.

Pop

 

[blackhawk]

After watching some videos on the lock miter joint, I am leaning against it. I like the idea of miter joint with splines. This was a good video that I found showing 4 different types.

 

[Dan Bowman]

The Kehoe jig (Infinity tools makes something similar) makes strong and attractive miters using a sliding tapered dovetail spline. I'm not sure if he's still in business - the website is pretty old.

 

[Skymaster]

might be fussy, but That is what I do for the urns, lock miters. Once you get it setup :}:}:} it is a great joint

 

[Phil S]

I agree with Jack. I am lucky enough to have a shaper that I leave setup with an Amana lock miter. Works great - I never touch the adjustments

 

[Dreuxgrad]

A hassle, but I did a cased sixty inch opening when I redid the family room years ago. Not much stress on the wood, but plenty on me!

 

[Skymaster]

someone here invented setup gauges for the lock miter, sold it to Infinity Tools you can go there and buy them totally recommend them, simplifies the whole process

45° Lock Miter Router Bits & Patented Setup Jigs

Set up lock miter router bits for perfect joints in minutes, with minimal setup and less hassle!

www.infinitytools.com

 

[tvrgeek]

I'm with the too fussy group, though when I used mine, It was with a free-hand router and jigs. I have kind of moved from machine joints to hand cut dovetails. More patience in my old age? Na. Now my router is mounted, maybe I should try it again. Anything to avoid biscuits.

Can't find it now, but last time I used mine I had a bit of the MDF I used with it set up so I used it as the jig. Things migrate when you move, so it may be in some strange box.

 

[bowman]

someone here invented setup gauges for the lock miter, sold it to Infinity Tools you can go there and buy them totally recommend them, simplifies the whole process

45° Lock Miter Router Bits & Patented Setup Jigs

Set up lock miter router bits for perfect joints in minutes, with minimal setup and less hassle!

www.infinitytools.com

That would be Alan in Little Washington. https://ncwoodworker.net/forums/index.php?threads/lock-miter-master-patented.62364/

 

[sawman101]

Thanks Neal, for remembering the name, I sat here trying to remember and all I could recall was the Little part. He also invented the I-box jig. Haven't heard from him in quite awhile, but sure enjoyed his discourse on his inventions.