When I removed the bearings from the roller I noticed that they were very greasy - covered in lubricating oil. This material does not want to come off your finger. This prevents the bearings from rolling evenly.
FKG 99502HNR Bearing Width Pre Lubricated
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π Wheels Manufacturing Ball Retainer Bag: Convenient Storage and Protection for Your Ball Retainers
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Linear Clamping Support Bearing by Sydien
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Enhanced Performance Sydien SCS12UU Bearing Bushing Diameter for Precision Machinery
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