[Pat Fairbank]

A word of advice - we have used both the 3/8" double-sealed ball bearings from McMaster and the 3/8" double-shielded ball bearings that can be purchased from IFI/AndyMark/elsewhere, and I can tell you that the double-shielded bearings are vastly superior in quality to the double-sealed ones. The inner race on the McMaster bearings feels loose and has a lot of movement, and we even destroyed a bearing completely during normal operation on a shaft having a fair but not excessive amount of sideload on it.