I've made a bunch of them, for different sizes of box joints, and to replace the ones that I was not totally happy with. Then I bought an Incra I-Box jig, and after using it a couple of times I'll never go back, so all of my shop built jigs became fire wood.
Yes, the I-box jig is expensive, but it saves so much time in setup and use, and does perfect box joints so easily that it has been well worth buying. I have posted photos of some of my boxes and close-ups of my box joints made using the I-Box jig and Freud SBOX8 blade set. Do a search on my posts, if interested.
Central North Carolina