bike maintenance sprocket for 12mm through axle

For bike maintenance you may take off your rear wheel. Normally then your chain rubs on the frame which we obviously don't like to be scratched and all messed up. Therefore you can use this gear and slide it on your through axle without any other fancy equipment. You can now clean and lube your chain, all while switching gears and stuff.

ATTENZIONE | ACHTUNG | ATTENTION PLEASE:

• print flat side of sprocket facing the printer bed (has a curved and a flat side)
• print with supports
• after printing, you may need to use a drill bit or router bit or a reamer to fit the inner diameter to your through axle (its designed to be 12mm, but obviously 3d printing is limited in accuracy, depending on your slicer settings - mine printed out at 11.6mm and I drilled it a little oversized to 12.05mm)

It took me a few iterations to make the chain feel good on the sprocket (adjusting dimensions), but for me it is a pleasureable fit now :)
If you want to adjust it to your dimensions, you'll find the FreeCAD source file attached.