A company called Mecrob (Mecrobremake.com) produces some very unique and in some cases complicated kits for people to assemble. One of those is "Aethercore" a steam punk inspired motorized mechanism. A picture of the completed kit is shown.

I recently purchased this kit and found one problem during the construction process - part of the gear mechanism was not engaging properly due to a pair of elongated holes in a couple of the sheet metal brackets. These holes prevented the gears from engaging properly. The symptom is either that part of the mechanism does not move at all, or two larger gears occasionally skip or stutter. A picture shows the gap between the bearing and the bracket before installing the shim.

So I made some measurements and designed a "shim" that would ensure that the bearings in the two elongated holes would be in a position to properly engage the gears. Basically the shim fills the empty space between the bearing and the bracket. The 3D design is shown.

Take the STL file and make two of these shims. One goes on either end of an axle in the assembly. I made the shim using PLA filament and normal print settings. Printing two of these shims should take less than 5 minutes - they are small!

These shims can be installed on an Aethercore kit assembly even after the kit has been assembled. One side is easy, but to place the shim near the large gears will require some careful disassembly of the axle with the large gear to allow access to the axle you need to fit the shim to. If your kit works fine, then you probably don't need these shims. But if you experience the skipping gears like I did, you can then just install the shims on either end of the axle and this should resolve the issue.

A picture of the installed shim is shown.