One piece fixed roller for self centering spool holder

First I want to thanks 3D Sourcerer for the design, I wanted to make this type of model after seeing a documentary on trains which explained how the wheels and rails were made to avoid derailments, thanks to him I didn't have to do it from A to Z. But I ran into a problem while trying to assemble it. there was a gap between the half-body on the standard version and when forcing the assembly bowed. After analyzing the fusion model, I see that the bearing in the design measured 6.5mm in width, whereas a 608 bearing is 7mm. With only 0.2mm of clearance per side in the design this leads to 0.3mm error per side So i make it in one piece first, and then I increased the bearing extrusion to avoid this error and give a little more play to this design, this is not rocket science we can deal with 0.6mm of side play, and it will be easier to print. See pictures to understand This also fix this remix : https://www.printables.com/model/557004-self-centering-filament-spool-holder-roller-as-one#preview