How to cut box joints using shaper

[Timur Aydin]

Just got myself a nice combo machine and I'm eager to build my first project on it, a fruit cabinet. The drawers will be made using box joints. Most box joint jigs rely either on dado blades or a router table to get the job done. I don't have either of these available to me.

My combo needs optional upgrades in order to run high speed router bits or dado blades and I don't have any cash left to buy them. But the combo has a nice, powerful shaper spindle. If I buy a grooving cutter (OD = 120mm, ID = 30mm, cutter width 10mm) for the shaper spindle, can you think about a jig that will allow be to cut precise box joints?

I came up with something like this:

- Cut 10 or so hardwood rods (Rod A) whose width is exactly equal to the distance between the joint fingers. This should be easy to do with the thicknesser.

- Cut a hardwood rod (Rod B) whose width is exactly equal to HALF the distance between the joint fingers.

- Mount the grooving cutter to the spindle

- Take the drawer front/back pieces and clamp them to each other. Cut the first finger. Place one Rod A under the pieces and cut next finger. Continue placing extra Rod A's underneath and cutting fingers until all fingers are complete.

- Take the drawer left/right pieces and clamp them to each other. This time, start by placing rod B under the pieces and cut first finger. Then continue placing Rod B's underneath for subsequent fingers until all fingers are complete.

This relies on the precision of the distance rods. Also it is important that there is no sawdust between the distancing rods.

Do you see any problems with this method? Any other methods for using a shaper to cut box joints?

[Chip Lindley]

No doubt the "rods" (usually called "strips" if rectangular) will space the fingers of the joint if sized accurately. But, you must clamp the front/back, or side/side pieces to some solid, sliding fixture (like a table saw's miter gauge) to run them through the shaper cutter. This operation cannot be free-handed.

Cutting finger joints as you propose on the shaper, is limited to the height the spindle will raise. The spindle will have to be raised exactly the distance needed to cut the next finger, and the next, and the next. Any inconsistency must be matched on the mating pieces for any hope of the joints fitting together.

There are easier and more convenient ways to cut finger joints if you have a router table or a table saw. I believe the spindle shaper would be my very last choice. If you have never used a spindle shaper, you must understand how to use it safely, and what to expect if you don't! I view the shaper as potentially the most dangerous machine in the shop, if mis-used!

[Nathan Callender]

I believe there are shaper heads that contain all the fingers on a finger joint. So, you cut them all in one pass. For making one box, I highly doubt it's worth spending the cash though. :-)

You can cut box joints on the table saw without a dado blade - just use the regular blade and jig it up properly to get the spacing right.

[Peter Quinn]

I believe there are shaper heads that contain all the fingers on a finger joint. So, you cut them all in one pass. For making one box, I highly doubt it's worth spending the cash though. :-)

You can cut box joints on the table saw without a dado blade - just use the regular blade and jig it up properly to get the spacing right.

Yup, check out the Felder video where the guy makes a walnut desk completely with his felder combo machine. He uses a box joint cutter stack for single pass box joints. I can't seem to find the cutters on their site presently, even though they are listed on the accessories home page as a "new" featured item, it is a dead link. IIR that stack is around $1200, for which you could buy a heck of a lot of beautiful pre made dovetail drawers to your specs. A real lot. In fact unless you are in the box joint business, or are planning to compete with IKEA, that stack is a pretty silly investment. OUCH.

Anyway, I imagine you could build a little jig for the sliding table that works just like a TS dado set up, but moving in a different plane. You need an index pin glued into a slot cut by the cutter you will be using and a way to space it from the cutter itself. It could be as simple as making a slot in your backer board clamped to your slider fence then throwing a 20MM gauge block under this and reattaching it to the slider fence, thus moving it twice the cutters thickness away from the cutter, giving you "CUTER-SPACE-INDEX PIN SLOT". You could also make a sled from BB that simply rides in the slot in the sliders carriage. You are limited in terms of drawer width, but you should be able to pull off most standard sized drawers up to maybe 6"? Depends on the combo's spindle height. But I would think that for the price of one nice 10MM euro groover you could get a pretty decent dado blade and use the combo's slider to make the joints that way, and have more flexibility long term, assuming your combo has dado capability which many do. I know the router spindles are pricy, but they are still way cheaper than those finger joint cutter stacks!

[Timur Aydin]

No doubt the "rods" (usually called "strips" if rectangular) will space the fingers of the joint if sized accurately. But, you must clamp the front/back, or side/side pieces to some solid, sliding fixture (like a table saw's miter gauge) to run them through the shaper cutter. This operation cannot be free-handed.

I will clamp the pieces to the crossfence on the sliding table. There will also be a sacrificial piece at the back so that there is no tearout. The spindle does go high enough. Once I adjust it to a certain height, it will be locked at that height and the pieces will be moved up step by step using the rectangular strips. So I hope it will be repeatable through 5 drawers.

Thanks for reminding me of the potential dangers of the shaper. I will be using it for the first time ...

[Timur Aydin]

Here is what I found in a local shop that makes cutters:

http://www.sonmezoglukesici.com/sertmetalkanalfreze.html

Each cutter disk is sold separately, as well as the distance rings. The disk is 80$ and the distance rings are 7$ each. So a stack of 4 cutters comes out to be 350$. Cheaper than the Felder or Freud prices, but still too expensive. I think I will just buy one cutter disk and make do with it...

[Timur Aydin]

Yup, check out the Felder video where the guy makes a walnut desk completely with his felder combo machine. He uses a box joint cutter stack for single pass box joints. I can't seem to find the cutters on their site presently, even though they are listed on the accessories home page as a "new" featured item, it is a dead link. IIR that stack is around $1200, for which you could buy a heck of a lot of beautiful pre made dovetail drawers to your specs. A real lot. In fact unless you are in the box joint business, or are planning to compete with IKEA, that stack is a pretty silly investment. OUCH.

Wow, that's pretty hefty! I had inquired about the Felder dado set and that also had an astronomic price. This local cutter shop sells grooving cutters for 80$ a pop. I just hope it won't ruin my shaper spindle bearings because of balance issues.



Anyway, I imagine you could build a little jig for the sliding table that works just like a TS dado set up, but moving in a different plane. You need an index pin glued into a slot cut by the cutter you will be using and a way to space it from the cutter itself. It could be as simple as making a slot in your backer board clamped to your slider fence then throwing a 20MM gauge block under this and reattaching it to the slider fence, thus moving it twice the cutters thickness away from the cutter, giving you "CUTER-SPACE-INDEX PIN SLOT". You could also make a sled from BB that simply rides in the slot in the sliders carriage. You are limited in terms of drawer width, but you should be able to pull off most standard sized drawers up to maybe 6"? Depends on the combo's spindle height. But I would think that for the price of one nice 10MM euro groover you could get a pretty decent dado blade and use the combo's slider to make the joints that way, and have more flexibility long term, assuming your combo has dado capability which many do. I know the router spindles are pricy, but they are still way cheaper than those finger joint cutter stacks!

Hmm, the index pin approach makes sense, too. Just like the dado box joint jigs, but along another axis.

BTW, my machine is the Hammer c331 with the 2000mm sliding table. It didn't come with the dado option and getting any such option will be very expensive (customs, logistics, currency and tax reasons). Think I will have to accumulate a list of wishes and once I save up that much, buy them in one pop and pay all the fees one time...

[Timur Aydin]

Thanks for all the responses guys. I'll let you guys know how I make out...

[Larry Edgerton]

I cut mine four, and sometimes eight pieces ant a time with a sliding saw. If I do one drawer, I use blocks to lift two of the oposing parts up to the first pin height and clamp them together, but sometimes I do two drawers at once.

I have thought about coming up with a setup for the shaper with multiple cutters as I have six inches under the nut and many projects need no more than that. If I was doing it your way I would raise the cutter each time to a rule, doing all the parts and a spare at each height. It would be imperitive that your fence was square to your top/carrage so that as you raise the cutter your depth stays the same, but with a Hammer that should not be a problem.

Let us know what you come up with and how it works. Where are you?

Larry

[Timur Aydin]

I kept thinking about how you would guarantee an accurate meeting between the opposing parts if you raise the spindle for each finger. But then I realized that you gang cut the opposing parts :) So even +/- 0.5mm doesn't really matter. Hmm ... And best of all, no precision distancing stripes to cut!


Let us know what you come up with and how it works. Where are you?

Yup, will definitely be taking pictures as I do the parts. I'm in Turkey :)