Box joint jig for smt

[scoter99]

I found this nifty plan for a box joint jig at www.newwoodworker.com and it describes how to attach the jig to the miter fence of a traditional ts by drilling countersunk holes in the jig and threading screws through them and through holes in the miter fence. The million dollar question is how do you attach the jig to the smt fence realizing that the screws must be flush with the face of the jig. I suppose you could use T-nuts and screws that are almost the exact thickness of the jig. Do they make T-nuts that fit the front slot of the miter fence? I know someone out there has already thought of this! Why re-invent the wheel?

[Joe Lyddon]

Box joint jig for smt

Not too long ago, I saw a post for a Lynn's Jig... nicely attached to the SMT miter fence...

It looked very good!

Good Luck!

[Black wallnut]

Jeff at www.t-nuts.com has just what you need! Build the jig, drill and counter sink two mounting holes, use flat head machine screws just long enough to not bottom out in the T-nuts. There you have it!

[gmack5]

You can attach the Box Joint Jig to the Miter Fence Front Slot with small T-nuts (SM size).

I'd use the SM "T-nuts" with a #10-24 thread from T-Nuts.com. (Also available with 10-32 threads which are not quite strong enough for this application)

You'd want your Screw to stick out past the back wall of your Jig by about .250 but less than .299".

I measured the depth of the slot in the Miter Fence and it's .299 deep, so a protrusion of .250 would give you .049 clearance from the bottom of the slot, which should be more than enough clearance.

If you use 2 Flat Head Screws, #10-24 X 1" long on a Jig with a 3/4" thick back wall that should work just fine.

Don't forget to account for the fact that most Plywood is less than nominal thickness, be sure you measure your plywood thickness!

[scoter99]

Thanks everyone for the advice! I kinda figured I would have to go the T-nut route but I just wanted a reality check before I went off the deep end.