Box joint jig

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Project by Gianni posted 515 days ago 3250 views 12 times favorited 11 comments Add to Favorites Watch

After seeing the super cool Metthias Wandel machines, I decided to make this much simpler version of the box joint jig. I used a 16 tpi threaded rod with a nut pressed into the outer box, and loctite-ed two nuts with large fender washers on the inside box such that it could turn freely with little or no play. The 16tpi rod makes it easy to translate turns into inches in standard increments for the dado stack.

The first attempts to cut joints advancing against a standard blade resulted in failure, and it took a while to figure out that the cheapo saw blade i was using had less than an eigth inch kerf. Frustrating. I put in the dado stack with no shims and measured it at 0.495. That setup gave me a very tight friction fit with zero gaps… Happiness, save a concern that the joints wouldn’t allow any glue (I had to knock apart the dry fit pieces with a mallet). I added a pair of paper shims and that resulted in the pictured joint, which had a sliding fit that squared itself up nicely with some clamp pressure.

I can’t go as fast as the Metthias Wandel jig, as i have to turn 16 cranks between cuts and manually crank all the way back between pieces to “reset” the jig, but I won’t miss an extra 5 minutes per project, so that’s fine by me. I cut test pieces holding only the outer box and with my fingers over the edge of the inside box to put sideways tension on it during the cut. I thought this might make a difference to take out any slop in the lead screw, but it didn’t seem to matter – the shimmed blade leaves about a 1 mil spacing in the joints which seems to be adequate to account for any slop in the jig.

I’m very happy with the results, and thanks to Mr Wandel for the inspiration. His machines are nothing short of amazing.

11 comments so far

View Ampeater's profile


388 posts in 2350 days

#1 posted 515 days ago

I like it. Very nice.

-- "A goal without a plan is a wish."

View BusterB's profile


1350 posts in 611 days

#2 posted 515 days ago

Oh very ingenious….sweet jig

-- Buster, Ocoee TN (Critics are men who watch a battle from a high place then come down and shoot the survivors - Hemingway)

View woodshaver's profile


2738 posts in 1956 days

#3 posted 515 days ago

Nice job on the jig!
Nothing like having a sung fitting box joint. And I agree with you when you say Mr Wandel is an inspiration. He inspired me also, I bought his Horizontal Slot mortise machine plan and built it. I posted it here on LJ’s also.
I like the simplicity of your jig. Someday when I have the time I may build one like it.
Thanks for your post!

-- Tony C , My high school shop teacher said "You can do it"... Now I can't stop!

View a1Jim's profile


112001 posts in 2180 days

#4 posted 515 days ago

Cool jig nice work

-- Custom furniture

View Dan's profile


150 posts in 562 days

#5 posted 514 days ago

So you’re going to ship this one to me and make yourself a new one right? lol

Very nice jig, may just have to try to make something similar. The main reason I don’t do much with boxes is that I’m not good at doing joints, and can’t seem to cut a good miter to save my life.

-- Dan - Wooden Treasures CT -

View Ben Simms's profile

Ben Simms

191 posts in 894 days

#6 posted 513 days ago

Cool. i like how simple it is.

-- I played with Legos as a kid and I never had the part I thought I needed, so I learned to improvise. Now I'm an engineer with a woodworking hobby.

View helluvawreck's profile


15439 posts in 1470 days

#7 posted 513 days ago

That is a nice jig. I bet it works well.

helluvawreck aka Charles

-- If a man does not keep pace with his companions, perhaps it is because he hears a different drummer. Let him step to the music which he hears, however measured or far away. Henry David Thoreau

View RRGR's profile


54 posts in 1937 days

#8 posted 512 days ago

Cool version of the the screw advance jig. Time to save to favorites.

View wb8nbs's profile


138 posts in 1295 days

#9 posted 506 days ago

Know what you mean about turning the crank. After I lost count a couple of times and wrecked a project, I automated mine with an Arduino and a power seat motor.

-- The only difference between men and boys is the price of their toys.

View Gianni's profile


122 posts in 577 days

#10 posted 487 days ago

Wowza – did you do the design and programming for it? Very impressive. How does it stand up to sawdust?

View wb8nbs's profile


138 posts in 1295 days

#11 posted 487 days ago

Ya, all my stuff. I wanted to see if full extension drawer slides would work in that application. So far I haven’t had a problem. The shop vac plugged into the end of the jig gets most of the sawdust and I do have an aluminum channel I can sit over the left hand slide if I’m doing something really wide where the blade will throw sawdust in that direction.

-- The only difference between men and boys is the price of their toys.

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