These are the finished pictures from the tiny track dog project. (Man, that was a long time ago.) And the results were: success! They worked like a charm. There was no cable slip, no binding in the track, and the travel noise was minimal. We noticed that the UHMW bowed (approx 1/32″) at the bottom when the cable was tightened down, which was expected from such small bits of hardware. Nick simply pre-tightened the cable, and carefully shaved the dogs on the tablesaw — done.
The track was shaped from composite lumber (Home Despot decking). It ended up cheaper than the equivalent amount of UHMW, slicker (& quieter) than lumber and was less fiddly than strips of maso or arboron. It was also much gentler on our blades & cut mucho quicker than UHMW would have.
You need small, ad hoc, weld-on bearings? Check this out. Use a plastic bushing, a shaft collar and a cone-point socket set screw. Weld the shaft collar over a hole, and keep the plastic bushing in place with the set screw (the cone point is key). Feel free to add a little threadlocker if you’re paranoid. Works like a charm.
Found out a couple of pitfalls when building flats with mirrored acrylic skins. Our usual acrylic adhesive is a two part methacrylate based adhesive. It works incredibly well when bonding acrylic to just about any substrate (steel, wood, other plastics…) Some formulations cure to a relatively clear finish, which is quite the selling point. Unfortunately, we found that methacrylates will distort the mirror coating on mirrored plexi. Whoops. You can see the distortion in the picture below. It’s probably better to stick to liquid nails next time. As a side note, 3/16” mirror acrylic does not look great with toggles on 2’ centers; I recommend a thinner acrylic sheet contact cemented over a plywood skin to realize a flatter surface.