Bear X End Mount for E3D 20T Idler

thingiverse

E3D is selling very high quality Gates idlers with wider dimensions and a different inner diameter than the commonly available idlers used on Prusa printers. User tetra3dprint came up with an ingenious idea to modify the Bear X-axis idler mount, allowing use of one of these E3D/Gates 20T idlers. His design utilizes an adapter to accommodate those currently using smaller idlers and reusing their existing idler axle (typically a dowel pin). My design eliminates the need for an adapter. To make it work, you will need to source a suitable axle. Here are some options: * Source 4.95mm drill rod from McMaster Carr, cut to length. This can be found at https://www.mcmaster.com/2900a299. * Use "Go plug gauge", cut to length, which has a precise diameter of 4.99mm for a perfect fit. If that is not available, I have tested sizes down to 4.95 and they work well. You can find it on Amazon at https://www.amazon.com/dp/B002710PAU/ref=cm_sw_em_r_mt_dp_U_.aizCb7JR6AEH. * Go / No-go plug gauges from McMaster Carr, cut to length, are another option. Here is one that is 4.97mm with a stated tolerance that should work (but untested). You can find it at https://www.mcmaster.com/2281a2. * All3dmakers sells a 15.8 mm length, 4.95mm diameter dowel pin that is the perfect length and requires no cutting. It can be found on their website at https://all3dmakers.com/products/bear-x-axis-dowel-pin-for-e3d-gates-5mm-bore-idler. * You can also use a 5mm diameter dowel pin (commonly available) that has been turned down to slightly under-sized. To do this, you can chuck the pin in a drill and use the drill to spin it against a piece of fine (~800) grit sandpaper. For any of these options that need cutting to length, any length between 15 - 16mm will work. EDIT (2018-12-26): I added a V2 version of the idler that tightens up spacing to improve strength and firmly holds the idler by its bearing so that there is zero side-to-side movement. When inserting the idler, you will have to apply some force to insert it. It should click into place and then spin freely. This version also corrects an issue with the original Bear design that (for me at least) caused bridging issues. I'm leaving the old version up there in case people have issues printing the higher tolerances required for the new part.