Spool holder support

The standard Prusa Mk3 spool holder is fixed on one side only and bends somewhat under the weight of the spool. Whilst this has never actually caused a problem and it is easy to add and remove filament spools, I feel it needs support from the other side of the spool, especially when heavy reels are used. There are a few designs out there but I didn't see one that kept the best features of the existing holder so I came up with this.

This two part design is simple and fits the standard spool holder, which is not modified in any way.

The shape of the support arm is taken straight from Prusa's spool holder (hope you don't mind Joseph) and trimmed both sides. Also, the detent that locks the arm to the frame is removed so it goes on the frame easily (don't worry it won't slip off). I added a bayonet hole for the twist pin - a removable pin that locates into the center hole of the standard spool holder shaft and twists 90 degrees to lock into the support arm.

This spool holder supp