SummaryI had some bearings leftover from my Cobblebot build and other spare parts. I needed a few Idler pullies for a belt system I was working on so I designed this conversion kit. The 2 outer pieces press fit onto the outside of the bearings and each other to create flanges for a GT2 Timing belt to rest in. There is a 7mm gap between the 2 flanges. By scaling the Z axis this could work for other width belts. The 2 inner pieces press fit onto the inside of the bearings and each other to create a centered screw hole for an M5 Screw. These 2 pieces also ensure that there is no binding by created a gap between the bearing and any fasteners you use. An additional set of 2 inner pieces can be used as a spacer if you need the idler to sit father from whatever it is resting on. Be warned all of these are intended to be a very tight fit. I used 0.1mm gap and 0.2mm gap so that the parts would not slide when in use. I assembled mine by hand but you may need a vice or pliers to get everything together. If your printer is not producing mostly round circle or over extruding you might need to clean up the parts to get everything to fit. Print SettingsPrinter Brand: MakerBotPrinter: MakerBot Replicator 2XRafts: NoSupports: NoResolution: .2Notes: Many of the parts are using a multiple of 0.2mm so I would recommend that layer height. You will get one layer in some places and 2 laters in others. Additionally, The smallest wall is 0.49mm and my slicer only wanted to draw it with a 0.4mm extrusion width. If you are seeing strange behavior with the smaller part that's probably the explanation. You shouldn't need support or a raft.