I needed a better way for the roll to turn on my Velleman K8200. I put a bigger edge on the files, the pic is the first version that works but the files here hold better. Print 2 end caps and one tube part. Put on one round end cap , then the tube. Put your PLA on and then the other end cap. Fit the end caps into the roll evenly and then put your metel washers and nuts back on. Tighten but let the roll of PLA turn freely.