Belt Tension Gauge

thingiverse

A simple gauge for ensuring there is even tension applied to the belts on a Core XY printer. Specifically designed and tested against the SK-Go though it will probably work just as well against for many Core XY printers. The gauge contains two kinds of wheel. One that takes a OD16mm ID8mm ball-bearing bearing (preferred), and the other that does not require a ballbearing. I weighed 500g of sugar including a plastic bag which I then attached to the gauge. I held the gauge against the centre of the rail on each side of the machine to test belt tension as shown in the photos. The value of using this gauge became clear when, despite having used the "same tone" method, and generally trying to judge tension by prodding the belts, I found, my left belt measured 20mm on the Gauge and the right belt 9mm !!! A big and surprising difference (especially since the actual load will be logarithmic and in inverse proportion to the gauge measurements). I expected manually checking the belt tension would be inaccurate but I assumed the tone method would be good. It turns out it isn't (why this is the case was explained to me by someone who has a good understanding of harmonics). Wanting to avoid overloading the belts (which I have done before and is easy to do) I have equalised mine now on 15mm. The block with two pegs allows the gauge height to be altered for measuring the higher CoreXY belt (on the right of the SK-Go).