I created this side-brace to use with the related models, because I was unable to cut or order a length of 2020 extrusion to fit properly between the two side legs.
Note: This is just the brace in the middle. The upper and lower pieces can be found in the two referenced models. The original one includes models for 4 variations of the AMS as step files. The remixed one added another variation, and increased the width of the channel to 20.2mm as 3MF files. Both my AMS units happened to be V3, but some people have different versions, and may have to print the upper parts from one model and the lower from another. This middle brace has a 20.3mm channel and will fit a little loose, to easily position then fix in place using an M5X10 and M5 t-nut.
Update 1: I've added braces that can hold up to 6 build plates.
Update 2: I added another model to the list for new AMS with spacings of 72/73/72mm