QU-BD OneUp/TwoUp Pulley for Gantry Counterweight

thingiverse

I modified lwilder's Parametric Pulley Assembly SCAD file, giving you control over pulley radius adjustments and added a guiding system to keep ropes in place. The mount dimensions were also adjusted. It allows supporting gantries with counterweights; just stick the pulley to the top with double-sided tape and string it up. The current pulley size prevents rope friction when crossing overhead; however, larger weights require larger pulleys to prevent rope contact with parts. For counterweights, a small pill bottle filled with coins is an effective start, supplemented by large steel washers on strings. During my print, the X-axis shifted, requiring cancellation mid-print due to alignment issues. Using skate bearing pulleys decreases printed plastic and time. To begin: Specify bolt size in SCAD files or use M8 bolts and nuts if you work with STLs; 608 bearings are required for skate bearing pulleys. Secure tape at the bottom of the pulley mount to the cross-support's right bolt top. Tie a string from the gantry's highest wooden support to the counterweight so it just barely hovers above. Counterweights should be heavy and compact, with my original method consisting of a coin-filled pill bottle. A steel washer bundle is also an effective addition. Ideally, weight aligns perfectly at dead center on level ground but consider X-axis build plate clearance and weigh extruder loads separately; X axis often requires reduced support to avoid unnecessary weights on gantry's extended section