Upon attempting to print with Sainsmart TPU on my new MK3 I discovered the spool doesn't fit on the included spool holder. Since I just finished modeling a spool holder for the same reason on my CR-10 I decided to create a mount for it for the MK3. It's based on the factory spool holder but modeled from scratch in Fusion 360. If the fit is tight shave some material off the three ribs on the inside surface of the mount.
Fits filament spools with at least a 30mm through hole and maximum 95mm width.
Uploaded step files and added a shorter version of the mount for narrower spools (up to 70mm width).
All parts print in the displayed orientation with no supports required.