CNBTR 8mm ID 12mm OD 3.5mm Thickness Bearing Steel Mini Groove Ball Bearings DIY Industry MR128ZZ Pack of 10

These bearings were used to replace worn sleeve bearings for small lathe handwheel shafts. The small size outer race was appropriate for the minimal clearance available. The application is shaft stabilization in low speed application and for that purpose, these bearings are entirely satisfactory.

As described!

Well made, runs smooth, don't know the longevity yet.

Received a packet of 10 pcs. They all seem to work fine but have only used two in an application so far. No issues.

1 of the bearings was damaged and hard to rotate although with how many that are in the bag, this is hardly an issue considering that there are 10 in a package.

Measured with calipers, dimensions are all completely accurate which is great. 8 out of the 10 roll very smoothly and I will be using them. Of the other 2, one grinds a bit and locks up every rotation, the other spins freely but grinds very roughly. I need smoothness so I won't be using those 2.

I have purchased these MR128-ZZ 8x12x3.5mm several times and never had any problems. But this last batch I received, all the bearings have a significant amount of play. I still had a few from the previous purchase and they have much better tolerances.The parts they get pressed into makes it really difficult to remove them without damaging the part, so the parts are now toast.Lesson learned, no more cheap Amazons bearing for me.

A 2mm rod will not pass all the way through the 2mm ID by 5mm OD BY 2.5mm wide bearings, rendering them completely useless for my purposes.