I've optimized my Hario Skerton (with an anti wobble bracket) and had trouble refitting the original metal bracket, that holds the outer grinder in place. It was a little bit too big to fit perfectly. Thus, I designed my own one that fits exactly right.

Compared to the original:
- tighter fits
- longer bracktes to hold the grinder in place

It should be fine printing this from (non  food-safe) PLA, as it won't touch the coffee ground.