Rolling along

I woke up the other morning unsettled. I came to the realization the night before that the plastic bushings I was hoping to use for the reciprocating shaft were not slippery enough. Too much friction.

I fell asleep trying to think of a pre-made product that had solved this problem for me and could be reconfigured to work on my project. Nothing came to mind. I was stumped.

This same day, purely by chance I was helping my son with his skateboard when the solution struck me. Skateboard bearings! But what to mount them in? And how many? Where have I seen something like this?

After a little mock-up I decided that I needed three bearings in a triangular orientation. In theory this sounded great, but in practice it might be too much precision engineering for a guy with a dremel. But, I managed to find a helper in the form of a copper fitting.


The piece on the left is what I started with. A 3/4 female sweat to 3/4 threaded fitting. Commonly used, which must be why I had two of them in my spare copper box. Using the Dremel, I cut a notch in every other side large enough to slide a skateboard bearing bolted together with a 't' nut and washer for smooth rolling action. The piece on the right is what I ended up with. Notched and ready for the bearings.

Below right is the first one after soldering on the bearing cartridges. I'm quite pleased with myself–it rolls nice and smooth, allowing the 1/2 copper shaft to slide back and forth.

Now I just need to make another one.