I've been working on a way to make these jigs a few at a time. Right now I'm trying to decide the best way to make the base for the main part of the jig to slide in. The materials used in the pictures is all cold roll steel which has a nicer finish and should be a little harder than hot roll. That also means it's more expensive than hot rolled steel.
What I would need to know is how many people would want the cold rolled style base like I'm showing or use the hot rolled angle iron base like the original 555th jig. I think to make the newer one work better it will need a base and some gussets to keep the middle from expanding. It would probably be a good idea to do something similar on the angle iron base also.