Feedback on the box joint jig plans has been very positive, but there is one part of the building process that some have a problem with: cutting the division plate accurately. I thought my method of cutting was good, but it does rely on the ability to set the fence precisely for each cut. Also, fence systems are not all created equal and it can be a real challenge to set it up for one cut, let alone 56 without making a mistake.
So, I’ve been thinking of ways to either change the division plate to a ready made manufactured product (like threaded rod, that I experimented with here), or figure out a way to make cutting it easier. My latest idea was using a piece of shelf standard (also known as pilaster strip) for the division plate, but found that there were too many problems with that implementation. Instead, I came up with the idea of using that same shelf standard to make a simple jig that will help cutting the original division plate.
I start by cutting a groove in a piece of pine that is about 2″ wide and 24″ long and screwed in the shelf standard:

This is then attached to an ordinary table saw sled.
The rather surprising thing about these shelf standards is that they are very accurately made, with the shelf clip holes spaced exactly 1/2″ apart. I have measured many of these and found them to be the same. This is important for my jig design, since it relies on that overall accuracy to be able to cut stock in two passes on the jig.

This is the primary reason why I gave up on using threaded rod, since I could not find rod that had an exact thread pitch. Most of the ones I measured lost (or gained) 1/32″ (or more) over a 12″ length.

The rectangular shelf clip holes are exactly 1/8″ wide, so a 1/8″ drill bit will fit in with no slop.
I added a stop to the end of a strip of 1/2″ plywood and drilled a 1/8″ hole through that lines up with the holes in the shelf standard. I then took that drill bit and put the shank through the hole so that it sticks out of the plywood slightly.

The bit then locks into one of the shelf clip holes. This becomes a very simple, but very precise indexing system for spacing cuts exactly 1/2″ apart:

Since the division plate needs to have notches that are 1/4″ apart, a 1/4″ thick drill bit is used as a precision spacer. Make sure that you measure the bit to confirm that it is actually .25″.
Each time the jig is advanced to the next shelf hole, two cuts are made, one with the 1/4″ spacer and one without.

It really works very well and took very little time to do:

I made a video showing how it works:

This method will be used for cutting the division plate for the newer box joint jigs, and may be useful for other applications that require exact spacing.