Box Joing Jig

[Jerome Hanby]

Anyone ever build one to use brass setup blocks for the pin? Looks like the Whiteside set is less than $11 and contains 1/8, 3/16, 1/4, 3/8, and 1/2 sizes. Seems like some clever way could be devised to use the setup block to set the spacing then clamp it into place for use as the pin...

[Lee Ludden]

I used some 1/4" square brass tubing to make a dedicated size box joint sled. Same idea, it worked well.

[Alan Schaffter]

Anyone ever build one to use brass setup blocks for the pin? Looks like the Whiteside set is less than $11 and contains 1/8, 3/16, 1/4, 3/8, and 1/2 sizes. Seems like some clever way could be devised to use the setup block to set the spacing then clamp it into place for use as the pin...

There is one problem with using setup blocks for the indexing pin and to set the gap, and it can vary depending on whether you are using the jig on a router table or tablesaw.

On a router table, you must ensure the router bit is exactly the size of the setup block (actual kerf, not published size)- some router bits can be off a few thou which can affect the fit of the joint.

The tablesaw situation is similar but slightly different and can be much worse- you must stack your dado blade so the kerf it cuts is exactly the same as the setup block- that can take a fair bit of trial and error during setup since many dado blades do not cut a kerf whose width is exactly the sum of the published widths of the individual trimmers and chippers. A few years ago someone called Forrest on this and one of their engineers said (true or not) they make their dado blades slightly under-sized, so you need to use shims most of the time to achieve precise fractional sizes.

Finally, like any box joint jig, you must still set the gap between the cutter and the indexing pin to the exact width as the kerf as well. Unless you make a fence for each size finger you will need an adjustable jig or one that has many fences (I tried that once- had a jig with 6 fences). If your dado kerf is not exactly the same as the setup block, then the gap will be wrong as well and you will have even more error.

Bottom line- all dimensions- index pin, cutter to index pin, and cutter kerf must be identical and it is easier to adjust the other two to the width of the kerf.

Or you can just wait a few more days/weeks(??????), and buy an I-BOX from INCRA (http://www.woodmagazine.com/woodworking-tools/reviews/more/2012-wood-magazine-innov8-awards/?catref=wd200&page=4)- it doesn't suffer from these issues. :)

[Jerome Hanby]

Or you can just wait, a few more days/weeks(??????), and buy an I-BOX from INCRA (http://www.woodmagazine.com/woodworking-tools/reviews/more/2012-wood-magazine-innov8-awards/?catref=wd200&page=4)- it doesn't suffer from these issues. :)

Funny you should mention that. i have no plans on building another box joint jig, just recalled wondering about those setup blocks after I built my last one. I'm definitely thinking of buying the Incra jig. I've got a definite weakness for Incra goodies <g>