First Box Joint Test

So, if you hap­pened to read my post last month on injur­ing myself, you’ll recall I did so because I was hop­ing to make a box joint jig. A box joint, or as it also known: a fin­ger joint, is a series of over­lap­ping “fin­gers” along a joint. This style of join­ery gives lots of glue sur­face area as well as shear strength to a cor­ner joint. It’s com­mon­ly used for the cor­ners of a box, thus the name.

Well, I did man­age to make a first attempt at a jig and made a sin­gle joint test. I was hop­ing to use my stan­dard table saw blade with my sled in lieu of pur­chas­ing a dado stack1. The jig is a bit too loose in the cuts and it’s pos­si­ble my table saw sled is a bit too loose in the miter slots, as well. This com­bined with some cheap­er birch ply­wood (there are lots of voids and a very thin veneer) result­ed in the fin­gers look­ing more like a box­er who’d just fought Mike Tyson.

Some loose and chipped fin­gers

Also, the depth of the cuts were a bit too deep (which is easy to adjust, at least). But glu­ing up the loose joints was a mess.

You can see some of the over­lap here

I had sort of giv­en up on the exper­i­ment as a fail­ure, but I did recent­ly go back and sand the fin­gers down; this time on pur­pose (yeah, I get the humor after last mon­th’s inci­dent). The joint still does­n’t look great but it was­n’t as “gap‑y” as it seemed before cleanup. What’s more, I can attest that even as poor as this one looks, it is incred­i­bly strong. It’s not espe­cial­ly pret­ty, but for some util­i­ty box­es, it would def­i­nite­ly serve it’s pur­pose.

Noth­ing a bit of wood filler and fin­ish could­n’t make look nice

So, this was­n’t a total fail­ure and I did learn a lot from the exer­cise, includ­ing the injury. Which, my fin­gers have com­plete­ly healed back, nails and all. As a result of “baby­ing” the left index fin­ger, I did devel­op ten­donitis in my left elbow (which is real­ly the fore­arm mus­cles and ten­don con­nec­tion). So, that lit­tle inci­dent con­tin­ues to remind me to be safe!

  1. A dado stack is a pair of blades, often with inter­me­di­ate spacer/chippers in between which cut out a wider sec­tion of mate­r­i­al in each pass on a table saw. []