HELP - Box Joint Jig ugh!!!!!!!!!!!!!

[Ken Shoemaker]

Creekers.. I NEED your help!!!.. I worked for two days on making a simple box joint jig. This concept does not appear to be the most difficult of wood working task but frankly, I'm no closer to getting it than when I started.

PROBLEM - After making a 1/4" square peg and glueing it into the face of the jig, I then carefully measured 1/4" between the peg and the 1/4" dado kerf of the dado blade. So there is 3/4" from the outside of the peg to the outside of the kerf. However, for the life of me it doesn't seem to work. It's too tight and the fingers seem to drift.

I see Vaugh's beautiful work and sit here contemplating where my next move is, sawdust or scotch... Right now the scotch is winning.

Thanks in advance for your help.

[Andrew Ault]

It sounds like the space between the dado stack and the key is a little too narrow. This would also cause the two sides of a joint not to line up. This is why you see plans for finger joint jigs with a micro adjustment screw - it makes it easier to tweak the setup for a good fit.

In my experience, the gap need to be about two thousandths over and the key a two thou narrower than the dado stack.

I find that calipers help when adjusting a finger joint jig. Another tip is to apply pressure against the key constantly from cut to cut and to use a spring clamp to hold the workpiece against the face of the jig during the cut.

[Dave Falkenstein]

Here is a downloadable plan from Wood Magazine that I used to make a box joint jig that actually worked quite well:

http://woodstore.woodmall.com/boxjointjig.html

As I recall there is a very detailed explanation in the plan on how to set up the jig so the joints are nice and tight. Calipers that measure in thousandths are required to get it right.

[Don Baer]

Or just use a router to do the joints....:D

[Michael Ballent]

I agree with Dave... My dado set seems to be 1/64th too narrow so I have to add a shim to make up the space. Make sure that you are measuring the amount that is being plowed out with the dado set... That could be your problem...

[Gary McKown]

Good article on box joint jigs:

http://woodworkstuff.net/EDboxJCP.html

[Corey Hallagan]

I am deciding to make a box joint jig as well. One thing I have learned is that they need to be adjustable and have micro adjustable feature. Even if you use a router table it needs to be micro adjustable as the same problem exsists. The wood one looks good. Another good micro adjustable jig on Plans Now.

Corey

[Lee Schierer]

Here's a trick you may not have thought of.....Cut both sides of each corner at the same time. Stagger one board the width of the finger and then clamp both pieces together and cut the fingers in both at once. Be sure to number or mark the corners so you get the mates together during assembly. You also have to keep all the tops and bottoms the same direction. By cutting both at the same time any errors are replicated in each piece.

If your dado is wider than your tounge, each joint will tend to be a little further apart. THere was a really neat though not so simple jig in Wood Magazine a while back that is very adjustable. You could adjust the width of the finger and the distance from the finger to the next cut very easily. Once you dado was cutting the correct width slot, everything should cmoe out perfect. I made one but haven't taken the time to actually try it out.

[Vaughn McMillan]

(posted at 10:19 AM)...I see Vaugh's beautiful work and sit here contemplating where my next move is, sawdust or scotch... Right now the scotch is winning.

Well, there's the problem. I try to avoid the scotch until at least 11:00 AM. :D (Actually, I stopped drinking a few years ago, but it didn't seem to help my woodworking.)

Ken, the only advice I have to offer is to echo what others have said. My next jig like this will have some type of micro-adjust, but for now my jig is a simple piece of 3/4" plywood screwed to my miter gauge. Here are the basic steps I used to get it working...

1. I attached the ply to the miter gauge with a couple wood screws and cut one slot. (You could use clamps at this point and get the same results.)

2. I trimmed and sanded a piece of HDPE plastic into a pin that fit snugly into the slot I just cut. I didn't glue it, BTW. It is vital for the pin to be the same width as the saw kerf -- dado blades in my case. I didn't glue it, BTW...it's a tight fit so glue seemed unnecessary. I made the pin twice as long as I thought I'd need, because I needed two of them. One to go in the jig, and another to use as an offset when cutting the "mating" configuration of slots and pins.

3. I removed the ply from the miter gauge, and slid it over the width of the pin (same as the slot width). At this point, I reattached the ply to the miter gauge, but with clamps, not screws. Don't attach it permanently yet. Then, I made the second slot in the ply, which was pretty close to 1/4" away from the first slot. (At this point, I've not measured anything.)

4. Using a couple pieces of scrap pine 1 x 4 stock stacked together, I cut enough slots to check the fit. (Using the pin to register each cut, of course.) Invariably, you'll find the first few don't quite fit, but by moving the clamped-in plywood left or right slightly, you can tweak things and get the test cuts fitting nicely. As you adjust right and left, the second slot you cut in the ply (the one without the pin in it) will become a bit wider, but that's nothing to worry about. At this point, I didn't worry about the offset (mating) cuts. I just made wooden combs until two of them fit together. Once you're happy with the fit of the test pieces, then you attach the piece of ply to the miter gauge with the screws.

As I recall, I went through about 6' of 1 x 4 pine and an hour or so before I had things adjusted to my satisfaction. Throughout the whole ordeal, I don't think I measured a thing. It is a game of thousandths, but I preferred to do it by feel.

I should also note that I always clamp the pieces to the jig when cutting, and make sure they are all the way down on the pin and touching the table top. I found this to be especially important if you are cutting two or more pieces simultaneously.

I hope this helps. If not, have another scotch for me. :p

- Vaughn

[Bruce Branson]

This kit comes from Woodsmith.They send the hardware and plans and you provide the wood.It is 15.95.There are two micro adjustments for finger width and distance from the blade or bit.It also has a replaceable backup plate to control chip out.

[Michael Pfau]

Ken, I have found a router jig for box joints on the router table is much better then a table saw. Try that maybe

[Doug Cowan]

Here is some additional reading material for you. Below is a link to an article on a microadjustable fingerjoint jig with free downloadable plan from Popular Woodworking.

http://www.popularwoodworking.com/features/fea.asp?id=1109

Before you make any decisions though, tell us some more about the scotch :rolleyes:

[Ken Shoemaker]

My thanks to each and every one... The scotch is sdtill at the ready.. but this week-end I'll try every suggestion to get it right.. Thanks again.

[Kitty McKoon-Hennick]

I just finished building the WoodsmithBox Joint Jig kit and it looks very much like the one above on this page. I was confused by the directions all the way through, but now that the jig is done I'm really baffled. I want big joints, not dentil-like fingers, but this is the widest setting I can figure out and it looks like I would be cutting little more than a kerf at a time to make the joint.

http://www.deckwench.com/boxjoint.JPG

Did I misunderstand the abilities of this jig or am I not understanding the adjustments?

Thanks for any and all suggestions.

Kitty

[Peter Quinn]

What size box joints are you trying to make? On the TS or router table?

[Kitty McKoon-Hennick]

Table saw, and I'd like to be able to make them an inch wide.

I just watched the video that shows the jig in action -- http://www.youtube.com/watch?v=lmrGa_LDxoE -- again and I think I've built some part of it wrong. Sliding the adjustable material rest is an ordeal-- there's no nifty little spinning of the knurled nobs.

[Greg Peterson]

I've been working on a box joint jib myself. I've tried a number of different approaches and the two things that seem to be the biggest aid are dial caliper and a micro adjust on the jig. For me, without these two aids, I'm just making saw dust.

[Kitty McKoon-Hennick]

Here's the adjustment detail.

http://www.deckwench.com/jigdetail.JPG

It looks like the picture in the plans, but it certainly doesn't act like the jig in the video. The knurled nobs don't turn the rods, I have to use a open wrench to get any movement.

[Alan Schaffter]

Regardless of jig- the key is the dado blade (or router bit)- don't assume yours will be cutting precise 1/4", 1/2", etc. pins. First set your dado blade to cut what you want but don't mess with shims and don't worry if it is over or undersized. Use the dado to cut a notch in your fence then, and this is the important part, make a square peg that precisely fits that notch. Use a piece of the peg as a spacer to set the pin-blade spacing. Carefully lock the position of the fence.

Dado sets almost always cut a notch that is different than the sum of the published widths of the trimmers and chippers- they do not cut the stated width for a number of reasons- differences in dado blades, position of the shims, tightness of arbor nut, etc., etc. I've see at least one report where a Forrest rep acknowledged they machine theirs dado cutters undersize. It is possible to use the same cutters during different sessions and get different sized notches.

[Joe Scharle]

Here's the adjustment detail.

http://www.deckwench.com/jigdetail.JPG

It looks like the picture in the plans, but it certainly doesn't act like the jig in the video. The knurled nobs don't turn the rods, I have to use a open wrench to get any movement.

I've built that jig and assisted on 3 others and it should turn smoothly. I can't tell from here what the problem is, but it works great when it works. I suggest you disassemble and wax the slide faces. It could be possible for the threaded rods to be slightly mis-aligned and be difficult to turn. Just a guess.

And what Alan points out: everything is adjusted to whatever size slot the cutter makes.

I just saw your first pic and came back here to ask if your fingers are as large (thick) as they appear in the pic? Or is it just my tired old eyes? Here's the only pic on my computer, but maybe you can make out the fingers (the ones that make up the adjustable key)

http://www.ncwoodworker.net/pp/data/194/BoxJointJig3.JPG

[Joe Bradshaw]

Vaughn, I solved most of my box-joint problems when I bought Freud's box-joint blade. It cuts both 1/4" and 3/8". I found that if I cut a slot and then fitted the alignment pin in the slot, Iwas well on the way. Provide some adjustment in the pin board and cut some practice pieces. I built myself a dedicated sled to use when cutting box-joints. I can cut both sizes with the same sled. Clamping your stock is really important as is ensuring square cuts. Cutting box-joints is like real estate,practice,practice and practice some more.

[Kitty McKoon-Hennick]

Alan,

No worries, I don't assume the dado width is as advertised anymore than I expect the corners in my house to be square.

Joe,

How did you convince the knurled nob and the nut to stick together? If I try to move them counterclockwise they just unscrew from the rod.

[Michael MacDonald]

So there is 3/4" from the outside of the peg to the outside of the kerf. However, for the life of me it doesn't seem to work. It's too tight and the fingers seem to drift.

Ken -- I am pretty knew to woodworking, but this happens to be one decorative joint I have tried--only once and a few months ago. It took me a few test pieces to get it right... but not sure I could more easily do it again--I haven't made drawers in a while.

I did have to tune the placement of the jig in the miter gauge and add some shims to the dado stack to get the initial cuts just right. Obviously, you have to reverse the work pieces to try the first cut. I really got this first step to work from trial and error. At the time, I wasn't really up to measuring anything in the thousands, but I did have the shims that came with the dado set.

Once the first joint fit, I went ahead and cut a full row of test fingers. And again I had to make adjustments to erase the error that remained and was multiplied over the series of cuts.

I assume you are getting the first cut to fit, but you noted that the fingers seem to drift. Perhaps there is some drift from the work piece sliding on your jig? Do you have sandpaper on the face? or maybe pressure on the workpiece is the source--too much?

I also saw a NYW episode where Norm cut both pieces at once... makes a lot of sense and I will certainly try that next time.

I hope you got it nailed down today... tomorrow we are supposed to have nice weather again in Chicago!

[Floyd Mah]

My 2 cents. A while back, I built that jig that is showing up this thread. It is now disassembled and the bits are in my junk box waiting to be recycled as something useful. There is a fatal flaw in that jig. The two metal fingers which capture the previous cut notch in the finger joint will move when you fit the notch over them. Because of this very subtle deflection, you will cut joint after joint after carefully setting the fingers and the joints won't fit! The only way to get this contraption to work is to prevent the deflection with a small set of wedges or a set screw of some sort. As it is presented, and built by most, it is an idea that almost works, except that it doesn't. My advice is to not build it unless you have a plan for keeping the adjustable fingers from deflecting.

Sorry for the thread hijack, but it made me mad that I wasted time building this thing and I see it in some woodworking magazine every year pushed as a great aid to making box-joints. My only real contribution to this thread is that if you are using router bits to make box joints, they are sometimes off by just a hair (for example 0.239 inches instead of 0.25), just enough to throw off your joint. So, measure your router bit with a caliper before trusting the bit to be actually the nominal size.

[mreza Salav]

If you have an incra miter gauge building a jig with micro adjustment is very easy. I built the jig and did all 4 sides of 6 drawers in one afternoon.
Here are the pics of my jig on the Incra miter gauge:

147168147169

You can see the micro adjuster screw on the right side of the first pic which is just to the right of the flip-down stop. I loosen the screws that holds the MDF face of the jig to the miter gauge, adjust the screw a bit, and then re-tighten. A few sample tries and you get perfect fitting joints.

147170

It was my first try at box-joint and am quite happy.

[Alan Schaffter]

My 2 cents. A while back, I built that jig that is showing up this thread. It is now disassembled and the bits are in my junk box waiting to be recycled as something useful. There is a fatal flaw in that jig. The two metal fingers which capture the previous cut notch in the finger joint will move when you fit the notch over them. Because of this very subtle deflection, you will cut joint after joint after carefully setting the fingers and the joints won't fit! The only way to get this contraption to work is to prevent the deflection with a small set of wedges or a set screw of some sort. As it is presented, and built by most, it is an idea that almost works, except that it doesn't. My advice is to not build it unless you have a plan for keeping the adjustable fingers from deflecting.

Sorry for the thread hijack, but it made me mad that I wasted time building this thing and I see it in some woodworking magazine every year pushed as a great aid to making box-joints. My only real contribution to this thread is that if you are using router bits to make box joints, they are sometimes off by just a hair (for example 0.239 inches instead of 0.25), just enough to throw off your joint. So, measure your router bit with a caliper before trusting the bit to be actually the nominal size.

Excellent observation. The commercial version, by WoodSmith is not much better. If you make the pins thicker you lose the ability to make small fingers too.

[Ken Shoemaker]

I started this thread in 2005. I tried a few times to get it right. Just this Christmas I got an Incra V27 miter gauge. I may try it agian soon, when I'm done with this bottle ;).... Lotsa good info since I started this. BTW - I got a Porter-Cable 4212 Dovetail jig that has been working pretty well for me. I might try that as well....

Ooopps, my glass is empty..... Be safe, Ken

[Joe Scharle]

Alan,

No worries, I don't assume the dado width is as advertised anymore than I expect the corners in my house to be square.

Joe,

How did you convince the knurled nob and the nut to stick together? If I try to move them counterclockwise they just unscrew from the rod.

Just looked..I put star washers between the knobs and the nylocks. Don't remember if the plan called for them or not. Tighten with wrench & pliers. Mine turn easily, but I also spray dry lube on all threads too.


1325hrs:
Just tried to blow up your pic, but it's too fuzzy. Do you have jam nuts on both sides of the carrier plate? If not, the knurl knobs will tighten on the threaded rod instead of rotating the rod.

[John Neel]

I have made two jigs. One was a fixed size that was simple to make, but worked very poorly. That was probably due to my errors. The second was the same plan that Kitty McKoon-Hennick posted. It is a dream to use. Just get some scrap wood and practice a while. After you have the adjustments right, make as many joints as you want. I quickly made 6 boxes that I liked.

You might also try to find the original plans and instructions. I have them somewhere if you can't find them, but they are on the net in various places.

If you want wider fingers, you could adjust the plans.

[Dick Brown]

Don't remember where I saw this but was some time ago. Forget the micrometers, rules or shims. Build a simple sled, mine is two rail, make a second screw on fence to go in front of the main one to put your index pin in. Slot the back fence for the screws to be able to slide a wee bit.(1/4"--3/8") Put on your dado blade stack (or router bit if using a router table) Screw on your indexing fence with the screws about center of the adjustment slots. Set the rip fence against the end of this fence. Need to keep the rip fence locked in this place till you are done with the whole operation so if you don't have a way to cut the pin material after this lockdown, cut a solt with the dado stack in a scrap and make the pin material before locking the rip fence down. . Cut a slot. Make a long pin(three times as long as the pin needs to be)to fit the slot snugly. Remove the screws that hold your fence.Take two widths of the your pin, place them between the rip fence and the end of the indexing fence, and cut another slot. That is the one you will put the indexing pin into. Still not moving the rip fence, screw the indexing fence back on the sled with the end against the rip fence. Will be very colse to right. If you need to adjust it, make a mark with a scribe. Pencil mark is to wide.move very little at a time till the fit is perfect. Remember, anytime you move the index pin, you must cut two new test pieces. You can make any width joint you want just by making a new indexing fence. I made my sled rails a bit small and ran painters tape down the sides of them. If I want, I can get a very fine adjustment by taking off tape on one side and adding it on the other. Dick

[Kitty McKoon-Hennick]

1325hrs:
Just tried to blow up your pic, but it's too fuzzy. Do you have jam nuts on both sides of the carrier plate? If not, the knurl knobs will tighten on the threaded rod instead of rotating the rod.

Joe,

No, and that's a good thought. The plans are a bit awkward. Here's a tiny bit from the plans that I think stays within fair use--

http://www.deckwench.com/nuts.JPG

There's a brass washer against the wood on either side of the plate, but no lock washer or nyloc on the side with the knurled knob. I'll find some lubricant and reassemble the piece with a lock of some sort in place. Thanks.

Dick,

I will have to take your word for it-- I'm a total bonehead when it comes to reading manuals/plans. Without an exploded diagram I am lost.



It is a dream to use. Just get some scrap wood and practice a while. After you have the adjustments right, make as many joints as you want. I quickly made 6 boxes that I liked.

John,

I'm counting on that "dream to use" part. It sure looks great in the vid.

[glenn bradley]

I went low tech. Sometimes I over-think things. If I did them more often, I would definitly build an adjustable jig.

147194147195147193

[Kitty McKoon-Hennick]

Rearranging and adding to the hardware on the rod assembly did the trick. It's now

knurled knob-nylock-washer-wood plate-washer-nut-lockwasher-nut

I'll probably pickup another set of nylocks for the interior side of the plate to save space, but this worked well enough to give me a satisfying trial run:

http://www.deckwench.com/jigaha.JPG

Thanks for all the help. Now to build a box for the kid to keep her disassembled dolly parts in. Too bad I have to take off the dado head to cut parts.

Kitty

[Joe Scharle]

Good news indeed. Now if you haven't already done so; if you slide the dado stack off the arbor onto a stub dowel you will have your setup good to go when you're ready again. (blades, chippers and shims)

[Louie Ballis]

Ken, I have found a router jig for box joints on the router table is much better then a table saw. Try that maybe


I agree with this. I have found Woodline USA sells a "WOW router joint system" with three jigs that allow you to cut 1/4, 3/8, 1/2 inch box joints as well as half blind dove tail joints. In any thickness of material.

I havent used the dove tail feature yet but the box joints came out perfect (after I watched the instructional DVD a few times).

[Kitty McKoon-Hennick]

Good news indeed. Now if you haven't already done so; if you slide the dado stack off the arbor onto a stub dowel you will have your setup good to go when you're ready again. (blades, chippers and shims)
Hmm, I don't see any way to get the blades out that way as I have to access them through the throat of my Delta and it's a bit tight in there. The blades have to go in one at a time. However, I've got the blades numbered, so all I have to do is put them in as Left side, 3, 4, Right side and they should match up.