I had some tolerance issues with the original model, so I redrew all the components in Fusion 360, except for the center roller part. On my Bambu Lab X1 carbon, this printed well with just enough clearance to spin smoothly without excessive wobble.
I suggest using Arachne in the slicer, set to print with two walls and consider reducing your first layer line width to get a smooth first layer without gap fill. I ended up at 0.26mm for the first layer.
I also chose to print at 0.08mm layer height, but you can try larger layer heights.
I found plain PETG (no sparkles or additives) to print out smooth and offer low friction for this design.
Check out Amazon for your hobby supplies
(as an affiliate, I earn a small commission if you buy from Amazon, but there is no extra cost to you)
Assembly
Place the bottom shells as seen below on the table with the smaller one placed inside the larger one. Then lube the roller with some grease and place it in between the parts as seen below. Finally, place the small and large top halves and squeeze together. Spin the bearing to distribute the grease, ensuring you have smooth movement without too much wiggle. Wipe off any excess grease from the outside.
If you find the bearing to be too loose or too tight, you can attempt to scale some of the parts larger or smaller. You can also edit the provided Fusion 360 file, which has the dimensions defined in the sketches.
The author remixed this model.
Tolerance change