Bearings absolutely get small particles inside and bearing shields do not “seal” them, as people have already stated. I recently went over to using NSK platinums in my favorite throws, and (as also already mentioned) they don’t have shields. They also seem to be extremely sensitive to tiny particles, as they somewhat frequently go from nearly silent to quite loud.
YoyoFriends Philip @Mazdarx7FD posted an extremely helpful bearing maintenance video which has saved me loads of time compared to my previous bearing maintenance routine (soak, dry, lube every time a bearing would get loud). He shows that you can add lube (even way too much), then blow it out with compressed air. I’ve been doing this, or simply use my air compressor to blow out the small particles when it gets loud. Air alone has returned my NSKs to their optimal, near-silent state countless times in <30 seconds. I just thought I would pass along an alternative method to traditional cleaning methods that has worked marvelously for me. Thanks Philip!
