UPDATE: I replaced the lock nut stl with the correct one. Thanks for letting me know.
This centering roller fits directly on the OEM roller on my Ender 3 S1 Pro. No bearings, bolts, etc.
I suggest printing the halves vertically as that requires no support. After printing, a small amount of sanding was required at the edges/corners of the printed model to flatten the mating surfaces (see photo).
This printed well at 0.2mm and 0.28mm on my E3S1Pro, the photos are 0.2mm. I used 3 walls + 1 alternate with 10% gyroid (connected) infill.
I used PLA, but be aware that different rolls of filament may have different shrinkage properties, so use caution if printing pieces from different colors.
The author marked this model as their own original creation.