The plans for the new box joint jigs are nearly finished. I just need to go through them looking for mistakes and omissions. One good thing coming from this is that I’m getting better at making these plans. These ones will be my best yet, and are much easier to follow than the first version. I’ve also made sure that everything has sensible dimensions – part sizes are often whole numbers, with fractions being simple ones (1/4, 1/8, etc.).
Here they are, side by side for comparison:

The “big brother” is quite a bit larger and can handle four pieces of 1-1/2″ thick material and is capable of cutting stock up to 24″ wide (in two passes). It uses two guide bars and has a front guide track for the carriage. The advance lever setup and locking blade are the same on both jigs, but the division plate on the big one is 5″ longer. Overall design is similar, and they operate the same way.
I will be doing a new website article covering the construction of the bigger one to go with the plans. I will also be doing a construction video on the smaller model, and another video showing how to set up and use both jigs.

A little experiment:

I had some casting resin left over from when I was doing some of that type of thing a few years ago, and I thought I could use some to make a piece of flat plastic.
Seen here, I have made a form with aluminum bars and packing tape to cast a plastic strip about 3/8″ thick.

Taken out of the mould, it looks like a big piece of licorice:

Cut in two pieces and to size. One will be a division plate, the other a locking blade. This plastic is quite hard, but very easy to machine.

And those part completed:

Putting the division plate next to the scale on my saw shows the accuracy of my new way of cutting it. I have more details about that method coming in the next blog entry, on Saturday.

The locking blade:

The purpose of this was to demonstrate that these parts can also be cut from hard plastic, like acrylic sheet, and will be very durable and long lasting. They also look pretty good, and I’ll be using these to make my own new jig.