This is a caster adapter for 45x45 Bosch Rexroth aluminum t-slot extrusions. The fit is tight and I had to use a rubber mallet to hammer it on.
Caster attachment holes are 27.5 mm apart. To adjust them, adjust casterPlate_w to the width/length of your caster plate and set casterPlate_hole_offset to the distance from the hole to the plate's outside edge.
f3d file included.
The author remixed this model.