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.
![](https://www.jasoncoleman.net/wp-content/uploads/2020/01/IMG_2613-1024x768.jpeg)
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.
![](https://www.jasoncoleman.net/wp-content/uploads/2020/01/IMG_2615-1024x1024.jpg)
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.
![](https://www.jasoncoleman.net/wp-content/uploads/2020/01/IMG_2888-1024x768.jpeg)
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!
- 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. [↩]