Up Mini 2 X-Axis Tensioner

thingiverse

The Up Mini 2 x-axis stage is easily broken as the idler pulley is only held in place with a thin injection molded plastic piece that is always under stress. I needed a quick fix that was also relatively easy to install, so came up with this design. It copies the original geometry of the molded part, extending the base to allow a mounting hole through the circular mark left from the injection tool. This gives a precise reference (in my case 14.5mm behind the tangent edge of the bearing slot for the first drilled hole). The new part should then be screwed in, and the second hole can be drilled in place. There are two other designs I looked at prior to making my own - https://www.thingiverse.com/thing:3461323 and https://www.thingiverse.com/thing:3987766. Both have some issues in blocking the full travel of the stage, or requiring somewhat arbitrary holes to be drilled. I put a comparison picture of the original in middle, my design on the right, and the other closest design on the left. Possibly one of these other styles is better depending on how your plastic broke. Requires two 2.9m x 6-9mm self tapping screws. I use McMaster-Carr 94997A225 and 94997A250 because I already keep those stocked. Anything similar should work fine, or you can drill out the new part hole slightly larger if needed.