Install fit for PTFE lined plain sphericals

[cjccmc]

Looking thru a couple of supplier catalogs, the bearing OD to installation hole fit was recommended by some to be .0002" min clearance while another says min interference of .0003". We will purchase these bearings from MS part no., so don't know what supplier, could be multiple ones and the parts which receive these will be made ahead of time. Bearing OD is approx .656", CRES, grooved stake, low load application, installed in CRES part.
Any experience users of PTFE lined bearings who can provide guidance? Thanks.

 

[BearingDave]

Fits are always based on the operating conditions. The rule of thumb is, just like bearings, for the rotating ring to have a tight fit with its mating surface. For example, if you have a rotating inner ring and non-rotating outer ring, the inner ring will typically need to have an interference fit with the shaft.

Best scenario is for both rings to be have an interference fit, but due to ease of mounting it is most of the time not possible to use that. Inner ring rotation applications with a heavy lead require a tighter fit between the OD and the housing to prevent ring creep (where the outer ring rotates relative to the housing bore, something that is not desirable and can lead to excess heat and damage to your machine).

Therefore, in your case since you have a low load and probably a rotating inner ring application, a loose fit between the outer ring and the shaft will probably work.

See pages 70-77 of the following catalogue:

http://www.skf.com/files/886653.pdf