I build two basic styles of gantry cranes. One has both sides moving on track with the crane way stationary. The other has both sides stationary with the crane way moving back and forth. This particular build will be the later type. Once completed it will look something like below except this time I will attempt to place the control booth with the crane way so both can travel together.
The first sub-assembly to build are the side supports. A glue jig is a necessity to make all sides supports the same.
The two inner vertical members are H-8 columns cut to 7.5 inches. The angled supports are B-8 beams cut to fit. A-6 angles are glued to the four supports to hold them in place.
Once dry enough to lift off the jig additional B-8 beams are glued in place.
The side support sub-assembly is then turned around and A-6 angles are glued to the opposite side (aligned by eye).
60 mil thick styrene stock is cut to ½ inch wide by 3 ¾ inch long and glued to the support legs. The side support sub-assembly is now complete. Five more will be necessary.