I made this as a simple way of weighing the remainder of a spool. Place an empty spool on the roller and set the tare weight. Then put the partial spool on. That will tell you, what you have left on that partial spool. One of the first things that made me crazy, wondering if there was enough filament left on to run thru the night. I use a Dymo model P3 for the scale. I used bearings and the weights from a Fidgit Spinners, I think the bearings are 608. And Again, not coming from me, there are junk files in the images folder.