Woodgears Box Joint Jig

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Project by peterbb posted 844 days ago 3382 views 9 times favorited 9 comments Add to Favorites Watch

I recently made the Advanced Box Joint Jig from I found the documentation easy to follow, and the completed jig works well. Matthias now has a series of videos showing the construction of the jig.

I used 1/2” (12mm) plywood rather than the 9mm (3/8”)Matthias suggests, and had one minor problem as a result: the thicker plywood lifted the main gear so it wouldn’t mesh properly with the driven gear. I had to reduce the thickness of the plywood piece under the main gear by 1/8” to make it work. (I was also a bit sloppy in cutting the gears, which didn’t help.) I also foudn that the 5/16” knob that I first used to hold the main gear hit the gear, so I replaced it with a wing nut.

I used a Forrest Woodworker II blade to make the joints shown in the last picture. It makes a kerf just over 1/8” – just right to make a 1/8” joint with a single cut. For a 1/4” joint, I have to turn the 48 tooth main gear exactly 1/2 turn for a second cut on the first notch, then a turn and a half to start the second notch. For a 3/8” joint, I need cuts at 0, 180 and 0 degrees, then 2 turns to the next notch. Unfortunately this blade leaves a bump in the middle of the kerf, so the bottoms of the notches are a bit rough.

-- Peter

9 comments so far

View wild bill franklin's profile

wild bill franklin

128 posts in 897 days

#1 posted 844 days ago

Man ,this is a cool looking jig !! I would like to try making one of these one day . Nice job Peter !!!

-- wild bill, Stapleton, Al

View Martyroc's profile


2708 posts in 940 days

#2 posted 844 days ago

Nice Job, I watched Matthias’ video and he really tells you everything you need to know plus the plans are not expensive at all, for what the designs are.

-- Martin ....always count the number of fingers you have before, and after using the saw.

View luv2learn's profile


1680 posts in 936 days

#3 posted 844 days ago

Great job. I have his box joint plans and I hope my build turns out as well as yours.

-- Lee - Northern idaho~"If the women don't find you handsome, at least they ought to find you handy"~ Red Green

View Ken90712's profile


14878 posts in 1822 days

#4 posted 843 days ago

Very cool, I like it!

-- Ken, "Everyday above ground is a good day!"

View Rex B's profile

Rex B

310 posts in 884 days

#5 posted 843 days ago

Very nicely done Peter. I think this is one of Matthias’s coolest designs, and would love to build my own some day. Keep us posted on how it works for you.

-- Rex

View Barry Young's profile

Barry Young

10 posts in 1008 days

#6 posted 642 days ago

I just completed this jig and it is working very well. Thanks for the post Peter.

-- Barry Young

View JarodMorris's profile


165 posts in 1009 days

#7 posted 447 days ago

I’m finally ready to build this for myself. The best quality plywood I could find around here was 1/2”. Do you think I should plane it down to 3/8” I couldn’t find quality 3/8” at the box stores and I didn’t want to drop the money required at the local specialty store. I really like those guys in there and I’ll buy their pen kits and other stuff but I can’t afford $36 for a small piece of high quality 3/8” plywood.

-- Dad: Someone was supposed to pick up his toys! Son: My name isn't "Someone".

View peterbb's profile


36 posts in 921 days

#8 posted 447 days ago

As I wrote in my description, I used 1/2” plywood (Baltic Birch, if I recall correctly), and only had a minor problem with the gears meshing – easily fixed.

-- Peter

View JarodMorris's profile


165 posts in 1009 days

#9 posted 446 days ago

Oh, so you reduced the plywood UNDER the main gear that is on the block you move to select the smaller / larger gear? I was thinking you reduced the thickness of the gear plywood.

-- Dad: Someone was supposed to pick up his toys! Son: My name isn't "Someone".

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