Reversible Box Joint Jig - designed for Freud SBox8 box joint blade set

  • Advertise with us
Project by Mark posted 01-05-2011 01:45 AM 8105 views 14 times favorited 11 comments Add to Favorites Watch

I built this jig to work with a Freud SBox8 box joint blade set on the table saw. Borrowed ideas from a number of other LJer’s projects, and added some twists of my own. What’s different? Well, since this blade set is “reversible” to cut 1/4 or 3/8 slots, I decided to make a “reversible” jig that would hold settings for both of those designs, and minimize any need for readjustments.

The finished jig (photo 1) is symmetrical front-to-back, so it can be reversed and fed from front or back. I use it in one direction for 1/4” joints, the other for 3/8”. That way the zero-clearance slot in the sled base and the index pin size and position stays correct for each.

The sled base is 18” x 11” MDF with oak runners, one adjustable to take out all side-to-side play. For the upright part of the jig (photo 2) I just ripped a 3” strip of MDF, cut 18” lengths for the front and back, and cut 12 little 3” squares to laminat into support blocks. Before gluing up the assembly, I routed dual T-slots in the front and back to hold the faces, zero-clearance backup, indexing piece, and microadjustment reference.

I ran out of special metal T-slot nuts, so I ripped some hardwood into the appropriate shape to fit the slot (photo 3) then drilled and tapped holes (photo 4) and finally cut the strip into 1” pieces. Presto – 16 T-slot nuts for free. They won’t last as long as metal, but neither will I…

The facings for the upright were cut from some surplus birch hardwood flooring strips. I tried to show the various components in photo 5. “A” is the microadjustment reference. It is drilled and tapped for a 10-32 thumbscrew with wingnut to lock it. I keep this reference flush with the side of the upright and never move it. “B” is the indexing piece – it has a slot cut and the index pin glued in. To microadjust, you just loosen the screws that hold the indexing piece in place, tweak the thumbscrew on the microadjustment reference, and slide the indexing piece back against it before tightening the T-slot screws.

The zero-clearance backup piece (C in photo 5) can also be reversed, so it can handle two different finger heights (which should be just a little more than the thickness of the stock being jointed). The upper part of the upright holds a backing board (D) to provide enough vertical support and a safe place for my fingers to clamp the workpiece against the jig.

Picture 6 is my first test joint. Worked great! If anyone wants more details and I haven’t bored you to tears yet, I’m happy to share more. Happy new year to all!


-- Mark

11 comments so far

View Dan Hux's profile

Dan Hux

577 posts in 3574 days

#1 posted 01-05-2011 02:01 AM

very nice sled,

-- Dan Hux,,,,Raleigh, NC

View bigike's profile


4055 posts in 3488 days

#2 posted 01-05-2011 02:15 AM

cool sled/jig

-- Ike, Big Daddies Woodshop,

View AaronK's profile


1507 posts in 3664 days

#3 posted 01-05-2011 05:10 AM

thanks for posting this – i have that box joint set (very good quality!) and recently built a very simple box joint jig for it. I think i might take some of your ideas. nice work!

View smitty22's profile


714 posts in 3147 days

#4 posted 01-05-2011 05:15 AM

Nice Jig, you won’t be able to stop cutting the box joinits now!

-- Smitty

View NormG's profile


6283 posts in 3204 days

#5 posted 01-05-2011 06:20 AM

Great jig for the SBOX set. I have a set and they are wonderful

-- Norman - I never never make a mistake, I just change the design.

View Ken90712's profile


17594 posts in 3389 days

#6 posted 01-05-2011 12:00 PM

Great job on the sled. What a beast!

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

View zwwizard's profile


210 posts in 3909 days

#7 posted 01-05-2011 07:31 PM

Good Idea, I have one of the blade sets. I am wondering as to the quality of the bottom of the cuts. On my set , I get tooth marks and the saw cuts aren’t even. This the second set I got, the 1st set was really lousy. I may have to take the set out and get them resharpen. To late to take them back to where I bought them.

-- Richard

View Mark's profile


26 posts in 3931 days

#8 posted 01-05-2011 10:29 PM

Richard, I had some trouble with that blade set at first too, but the problem was with my tablesaw arbor. It wasn’t 5/8” dia along its entire length, so the two blades weren’t perfectly concentric, and that resulted in an uneven bite. I can post a photo if it would help.
I solved this by moving both blades over to the threaded portion of the arbor by using a blade stabilizer as a spacer. Had to make a new throat plate too. Good luck!

-- Mark

View zwwizard's profile


210 posts in 3909 days

#9 posted 01-06-2011 07:43 PM

My arbor is OK. It looks like one of the blades is a tad larger or I have a tooth that a little bit higher than the rest. I think the only course is to give it to the saw shop and have it checked out. they have a CNC machine that does the sharpening.

-- Richard

View Jiri Parkman's profile

Jiri Parkman

953 posts in 4013 days

#10 posted 01-07-2011 01:28 PM

Perfec jig and nice performation.

-- Jiri

View exelectrician's profile


2328 posts in 2627 days

#11 posted 10-07-2011 07:01 AM

Quality built in quality joints out – I admire your craftmanship.

-- Love thy neighbour as thyself

Have your say...

You must be signed in to post the comments.

DISCLAIMER: Any posts on LJ are posted by individuals acting in their own right and do not necessarily reflect the views of LJ. LJ will not be held liable for the actions of any user.

Latest Projects | Latest Blog Entries | Latest Forum Topics