Longer Arm and spool Adapter for Prusa spools

thingiverse

Almost all of my PLA is 1 kg Prusa brand filament that uses large, almost 9cm wide spools with a relatively small center hole, exactly 50mm in diameter. The wide spool would not fit on the original arm without completely covering the hole for the rigid end cap that keeps the spool from sliding off the arm. To adapt to these spools, I made the arm longer by more than 2cm to have plenty of room for the spool to spin freely and also use the end cap. In case someone makes even wider spools than what I have, this modification ensures they will fit as well. Additionally, I beveled the top edge of the arm base to save on printing time and filament used without sacrificing structural strength. I also trimmed the top of the arm around the safety pin hole where it was rounded beyond the area where the spool would sit. This was mainly to address strange issues Slic3r software had with creating support structure for the arm when printing it vertically. All of the included adapters were larger than 50mm Prusa spool hole, so I modified one of them to make one that is a little under 50mm in diameter and lengthened to account for the spool width. In my experience, using Slic3r and Prusa i3 Mk3, the spool can be printed without supports. Please note that I added a bit of extra cylinder poking out of the "top" of the spool in the direction it's meant to be printed. Since the arm is holding up to 1kg of weight, I would recommend printing with at least 40% infill to have a lot of connecting structure throughout the shape and not relying on the outer layer's connection between the round arm and the square arm base. I will be testing this in the next few weeks and adding photos. These parts were modified in Maya from JeriStyrman's MK II rigid spool holder files, specifically the arm and Hatchbox adapter STLs.