Box joint jig

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Project by Gianni posted 03-02-2013 12:53 PM 5820 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


441 posts in 3951 days

#1 posted 03-02-2013 02:21 PM

I like it. Very nice.

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

View BusterB's profile


1970 posts in 2211 days

#2 posted 03-02-2013 02:40 PM

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 Tony C   's profile

woodshaver Tony C

6229 posts in 3556 days

#3 posted 03-02-2013 03:40 PM

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!

-- St Augustine FL, Experience is the sum of our mistakes!

View a1Jim's profile


117340 posts in 3780 days

#4 posted 03-02-2013 03:47 PM

Cool jig nice work

-- wood crafting & woodworking classes

View Dan's profile


159 posts in 2162 days

#5 posted 03-02-2013 08:00 PM

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 2495 days

#6 posted 03-04-2013 01:23 PM

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


32087 posts in 3070 days

#7 posted 03-04-2013 01:25 PM

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

helluvawreck aka Charles

-- helluvawreck aka Charles,

View RRGR's profile


54 posts in 3537 days

#8 posted 03-05-2013 03:39 AM

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

View wb8nbs's profile


164 posts in 2896 days

#9 posted 03-11-2013 02:07 AM

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


232 posts in 2177 days

#10 posted 03-30-2013 11:23 AM

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

View wb8nbs's profile


164 posts in 2896 days

#11 posted 03-30-2013 02:50 PM

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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