This is just a slight modification on lawsy's carriages. I've added a tighter fit to them so that you should be able to snap fit the bearings without any wiggle room. It is a tight fit on my printer, so it might be too snug for some. Let me know if I need to fix the tolerances any, but for me it worked fine. Note: I typically wait until I've fully used a remix/design I've published before putting it on thingiverse, but due to the fact that this is only a slight change to lawsy's design it should still work fine. I have already printed out all parts and the bearings snap in perfectly. I am sure that the remaining functionality of the carriages remains the same as before.