Belt Tension Set

thingiverse

Basic-Basic Belt Tension Set for Prusa i3-Mk3 Printers. Place the cup end on a scale with stand on the table top, fill it to read 200 grams, then attach the lid which friction fits but can be secured with glue. I've used lead pellets and 1/4" steel shot effectively. Tie a short thread between the beam end and belt hook, adjust so the hook connects with the Y belt when the beam is level. The beam end can be used for X. Adjust printer Z until the belt is just below the beam (about 1/8th inch). 200 grams should pull the lower Y belt up about 12/64" ... about 6 lbf static tension. 200 grams should pull the lower X belt up about 15/64" ... about 6 lbf static tension. Gates GT2/GT3 1/4" (6 mm) belts are spec'd at a minimum of 2 pounds, and a maximum approaching 25 pounds (100 lb/in). 250 grams with the same deflection is about 8 pounds force tension on the belt. I've attached my updated worksheet - if anyone wants to double check and comment. There are other ways to measure tension, but this seems simple enough to share. The idea is to get belt tension in the ballpark, not to some finite tolerance.