I needed a special fence for routing lock miter joints. I found one designed by Norman Ellis who sent it in as a tip to another website. The fence I made below is 7” tall. It can be clamped to your regular router table fence. I jointed the top and bottom edges of this fence making sure that they were parallel.
Click to enlarge photos
Here it is with the sliding fence mounted and another pic with a workpiece clamped onto the slider. When you rout it you should hold the lower portion of the workpiece with medium hand pressure pressing it toward the fence without getting your hands anywhere near the bit.
Some slider details: The 2nd shot is the back of the slider.
Her are two pics of a routed lock miter joint. Keep in mind that this is construction quality Fir. Note the tear out on the trailing edge. This is normal with LM bits, but a thin Ply backer between the slider fence an the workpiece might reduce that. I haven’t tried it yet. Unless it is plywood you should route lock miter joints in one go to prevent chipping.
More good news! you can also use this set-up to rout tenons. The faces are routed with the workpiece clamped in the jig as in the first photo.
I routed the edges by clamping one of the other tenon workpieces in the slider and then holding the current workpiece edge against the fence and it’s face against the edge of the one in the clamp. It was routed like this being hand held.
The tenon routing finished
The routed morise (which I messed up a little lifting it off the spinning bit)
Here the tenon edges have been rounded to match the routed mortise.
And finally a dry fit. What do you know? It came out perfect!
I hope you find something interesting here and get some use from it. Thanks for viewing.
-- Mike, American in Norway