I designed this spool holder to prevent my spool from getting stuck while printing. I wasn't happy with the stock equipment, so i designed my own. First  I went to pick up some cheap 2inch rubber casters from Harbor freight. Then to Lowe's aka home improvement store and picked up the hardware, IE threaded screw a few washers and a few nuts. Then took all my measurements and started designing. Printed a few out and they work great. Almost no resistance, smooth rolling. I printed them using Hatchbox PLA