Spool Bearing

I designed this part to adapt the spools I purchased from Makerbot to rotate freely on a 1" piece of conduit. This is not a ball type bearing, but functions quite well as a bearing by interfacing two hard surfaces (ABS and metal in my case)through a knife edge.

I found that when I simply hung the spools on the 1" conduit they hung off-axis and the Stepstruder did not have the torque to rotate the eccentrically mounted spool. Simply adding this adapter to re-center the spool solved the problem and it feeds beautifully.

Originally I just built the adapter, but I found on long builds that the spool tended to "walk" off. I added an end piece to hold the spool on and used a couple of small screws I had available to fasten it in place.

The parts are designed to minimize the amount of ABS used. All walls are designed to be 0.125" and I cut a number of holes out of the hold piece simply to reduce waste.

The picture makes the adapter look like a big fat cylinder, but in fact only the ends are actually 1" internal diameter (ID). There is a small 45 degree solid to create the adaptation from 1" ID to the outside diameter so that it only contacts the conduit in two small knife-edge places.