My PTFE tube had been rubbing against the glass and creating a flat spot. I printed one of those little “protectors” with the little nib on it but would not stay in place. I thought I saw a larger slip over protector but couldn't find it. So I designed one myself. This also let me begin to learn to use the emboss tool in Fusion 360. 

So here is a slip on cover that should stay in place and cover enough area to offer actual protection. I designed it with a slit in it to make it easier to slip on. I also found my original design was too tall and became unstable so I made it shorter. 

Probably don't need to say this but this needs a brim.