Lock miter bits for thicker stock (1.50+")

[Patrick Nickles]

I'm considering using a lock miter bit for several projects but I frequently use S2S 6/4 which ranges from 1.5" to 1.625".

I've not seen any lock miter bits which can handle stock bigger than 1 1/8" (MLCS product #7850).

I've never used a lock miter. Does anyone make a bit which can handle thicker stock?

[Anthony Whitesell]

If you cut the stock on a 45 with the table saw, you can use the lock miter bit on any thickness stock. In addition to the usual tricks of setting up the bit, you will need to adjust the height and fence so only the lock part removes any material and the beveled part is along for the ride.

[Peter Quinn]

Anthony's idea is brilliant, I don't imagine you will find a router bit to do 6/5-8/4 lock miters, think about how much stock removal that is. Routers can't swing that much cutter on a 1/2" shaft. We have a shaper cutter in the shop that will do 8/4 lock miters, it's almost 8" diameter and weights more than 10 pounds. I've done a version of lock miters where you spline the miters, assemble the first three, then bang in the last spline because you cannot assemble 4 splines on miters simultaneously. I've also tape mitered the first 3 sides and splined the last with good success. You don't really need a lock miter on long grain glue ups. They help with assembly on long pieces that are not particularly flat like box beams, for short legs I generally don't bother.

the other simple solution is....mill your stock to 1 1/8", what's the difference really?

[mreza Salav]

If you cut the stock on a 45 with the table saw, you can use the lock miter bit on any thickness stock. In addition to the usual tricks of setting up the bit, you will need to adjust the height and fence so only the lock part removes any material and the beveled part is along for the ride.

I'm interested to see how this can be done. I have a hard time imagining given that there are parts of the profile that extend out of the 45 degree cut.

[Anthony Whitesell]

I'm interested to see how this can be done. I have a hard time imagining given that there are parts of the profile that extend out of the 45 degree cut.

You are correct.

I did this once a long time ago and vowed not to again. I believe that was what I was also told and found the same thing.

I believe I ended up removing one portion of the table saw (a psuedo-45 deg rabbet). Then used the router bit to form the lock profile, followed by another trip to the table saw to remove the top portion. The trick is to remove the material below the bottom of the bit on the table saw, then use the router bit to cut the profile in the center, followed by the table saw to remove the portion above the router bit.

If you cut the stock on a 45 deg on the table and leave it long, there is less material for the router bit to hog off.

[Chris Padilla]

What kind of projects do you have in mind for the lock miter bit? They can be painful to set up although if you do go that route, you need this (http://www.infinitytools.com/2-Pc-Lock-Miter-Master-Jig-Set-For-3_8-1-3_16-Stock/productinfo/00-LMM/) so you don't end up HATING this cool bit. :) Personally, I'd steer away from the joint if you have other alternatives...especially since you want to use it on thick material that requires a shaper most likely as Peter said.

[John Goodin]

Woodtek 820-704 has 1.75" cutting height. Never used the brand so I can't vouch for quality. With such a large cutting face I'd trim off most with a miter first and with such a large piece of metal I'd be tempted to wear chain mail.

[Mike Schuch]

Many years ago a friend asked me to bevel some 2x6 cedar to use as the corner posts on his deck rails. I had just gotten my first shaper and the lock miter bit was the main profile I wanted the shaper for. So of course.... :D

I used every mm of the lock miter bit height which was about 1/4" shy of the thickness of the wood. This left a 1/4" x 1/4" grove down the outside of the joint which was declared an "Architectural detail!". After a liberal application of Gorilla glue he was thrilled with the results! :D