I want to use two plates back to back on a 20x60 vertical gantry. So far I'm thinking to mount them through the wheels but I'm not sure on what combination of spacers to use to make sure that everything stays pretty solid. I'm open to suggestions here, looking for some advice from the pros here who have ran into this situation before. I can follow up with some pictures of the build tomorrow.
For single thickness extrusions most people just put a mirror image of what is behind the wheel on the opposite side. I.e. if you have a 1/4" eccentric spacer behind the wheel, you put a reversed 1/4" eccentric spacer on the opposing side and fit that into one of the larger holes in the plate. And when it is eccentrics, be sure the orientation is the same to keep the wheel square. Overall there is really no mystery here. The wheel thickness is 11mm and there is 4.5mm to the face of the extrusion on either side. So if you want to cut blocks as spacers to fit between the plates (which is actually more solid than bolting through the wheels) just add up all the thickness and add about 2mm each side for clearance. For double width extrusions where double wheels are required, a 9mm spacer is the appropriate size to fit between them.
