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

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Project by Mark posted 1294 days ago 4410 views 15 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

-- Mark





11 comments so far

View Dan Hux's profile

Dan Hux

576 posts in 1970 days


#1 posted 1294 days ago

very nice sled,

-- Dan Hux,,,,Raleigh, NC http://whitdaniel.com

View bigike's profile

bigike

4031 posts in 1884 days


#2 posted 1294 days ago

cool sled/jig

-- Ike, Big Daddies Woodshop, http://www.icombadaniels@yahoo.com

View AaronK's profile

AaronK

1389 posts in 2060 days


#3 posted 1294 days ago

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

smitty22

590 posts in 1542 days


#4 posted 1294 days ago

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

-- Smitty

View NormG's profile

NormG

3977 posts in 1599 days


#5 posted 1294 days ago

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

-- Norman

View Ken90712's profile

Ken90712

14821 posts in 1784 days


#6 posted 1294 days ago

Great job on the sled. What a beast!

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

View zwwizard's profile

zwwizard

189 posts in 2304 days


#7 posted 1294 days ago

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 http://www.PictureTrail.com/gallery/view?username=thewizz

View Mark's profile

Mark

26 posts in 2326 days


#8 posted 1294 days ago

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

zwwizard

189 posts in 2304 days


#9 posted 1293 days ago

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 http://www.PictureTrail.com/gallery/view?username=thewizz

View Jiri Parkman's profile

Jiri Parkman

950 posts in 2408 days


#10 posted 1292 days ago

Perfec jig and nice performation.

-- Jiri

View exelectrician's profile

exelectrician

1459 posts in 1023 days


#11 posted 1019 days ago

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

-- Love thy neighbour as thyself

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