[Jared Russell]

1/16th wall AL round tubing with 1.25" OD has a ~1.12" ID, and 1.00" OD has a ~.87" ID. Perfect for common bearing sizes, and in the larger case, for AndyMark hubs too. Just clean up the ends of the tubing (or the hubs) on the lathe, press your bearings/hubs in, and you're good to go. Not too bad at ~.25 lbs per foot (more if you run the shaft all the way through the roller, but you can get away with just having a nub at either end).

For the "polycord" itself, we are just using 1" wide orange urethane flat belting from McMaster so we don't need to worry about grooves in our rollers. In fact, we actually just add a few layers of electrical tape the build up the diameter of the roller where we want the belt centered, and the belt stays put and doesn't wander.