Review on Improved Length Printer with LM8UU Linear Bearings by James Dominick

I bought these to replace some worn out bearings on my Prusa i3 MK 2.5 printer. Luckily I only needed one pair as these bearings are very volatile. Out of the 12 I received: 1 was a bit tight and didn't turn smoothly on a smooth rod. 4 felt very loose and had significant play. 7 were of acceptable quality - they moved slightly but still had some play. I tested them on a brand new inline rod and made sure to reel them back and forth to break them in. I also tested some of the original rods for reference. The bearings are from my printer and fit almost perfectly with little to no play which should eliminate core tolerance issues. I installed these bearings as a temporary fix to get my printer working again. I only had to replace some of the Y and Z axis bearings, so it's a good thing I didn't need all 12. To be safe, I stuffed them with fat. When I put everything back together, I immediately noticed that the axles on which I exchanged the bearings were significantly louder than before. I also heard a rattling noise when the printer made certain movements. I also noticed that the print bed wobbles a little more than before, possibly due to the increased bearing play. It was an acceptable amount (barely noticeable, but I heard a click as I shoved it back and forth), but more than I remembered with stock Prusa bearings. Despite all of this, I couldn't see much of a difference in print quality. Perhaps more accurate printouts will show the difference, but performance is acceptable for my purposes. Those bearings (at least the ones that worked) will probably be fine for now. However, it is disappointing that only a little more than half of the bearings in the 12-pack are usable.