Cone Ends Spool holder

I was wanting an adjustable spool holder, so in conjunction with my husbands mathematical brain we came up with this. We are using this on the original holder that came with the Anet A8 using 608ZZ bearings which slot into the recesses. This was also printed on the Anet A8 (which had made my bearing case smaller but the design has been adjusted for this and should fit with standard A8 print settings)