These are first box joints made with my box joint jig after
adapting it from my table saw to my router table. They aren't
glued up, which is my excuse for the gaps at the bottom of the
Here's the jig itself. It's based on the one in a recent Shop
Notes. I originally built this for my table saw, but I wasn't
happy about the quality of the joints I was getting with my dado
set. Instead of running in the miter slots, this version is
guided by the outboard runners. One of the runners can be
adjusted for a tight sliding fit on the table. The white insert
is hardboard. As in the article, it can be replaced when it gets
Got this comment from an anonymous visitor:
You can ditch the out-board guides. Put a collar in the
router table insert. Cut a dado in the bottom board of the jig to just fit
the collar. (Don't cut all the way through the bottom board, just relieve it
enough that the board fits over the collar, and make it a stopped dado, so
that the jig won't go farther than allowing the bit to be fully embedded in
the backer board.) (I'd show you a picture of mine, except my daughter
"borrowed" my digital camera and went on vacation.) The bit, of course, has
to protrude farther, but that is no sweat. Now you don't really care about
what angle you move the jig over the bit at - the collar will guide the jig,
and the stopped dado over the collar will limit penetration - no chance of
routing all the way through the jig (DAMHIKT).
You make a separate jig for each size finger joint, of
course. Works like a champ.
I don't know just where I saw this the first time - maybe the
"Router Magic" book, or some place like that.
Guess you make the dado first, then use the straight bit to cut the slot in
the bottom board and the fence. No alignment problems that way.
Seems like a great idea.