Now there is a closed one available as well. Whereas the original metal one needs a slit, the one made of PETG works way better without.
The original bushing is of some kind of metal, maybe even cast.
It is such rigid, the grub screws are near destruction until the bushing gets hold of the ball.
There is such a brute fore necessary to tighten the screws, every calibration purpose is way beyond belief.
Print this bushing with PETG and enough perimeters so that it gets solid.
I am sure this will not last a whole life, for me it works pretty well, although I made some for my stock.
No idea whether this could/would work with resin parts directly out of the elegoo.
Most probably too britlle...