This model is a replacement I made for the scroll wheel of my Razer Basilisk X Hyperspeed, as the shaft got snapped.

Instructions:

Print the 2 files, then cut a short stick of cylindrical plastic. For this, I cut a stick of filament for the 3Doodler around 3cm long. 

Stick the filament into the circular hole of the wheel, and the shaft print into the hexagonal hole of the wheel.

Open up the mouse with a Torx screwdriver (I didn't have one so I used a similar hex screwdriver). I believe you have to remove the bottom mouse skate in order to access a screw.

Take the logic board out, take the old scroll wheel out, and put the new one in. Cut the stick of plastic to be the perfect length to reach the middle click button.

Put the logic board and the scroll wheel into the housing again, and make sure the wheel works.

Close up the mouse, and hope it all works