In article , no spam says...

The spindle takes a pair of 7205 angular contact bearings that are held in
place by a locking washer and nut. I was able to find on the MRC site that
the torque on the nut should be 23-50 ft-lb. but can't seem to find answers
to the following:

Should the bearings be mounted "face to face" (where the contact lines of
the bearings converge inward), or "back to back"?

Just out of curiosity, were the originals bb or ff? My first take on
it would be to replicate the original setup.

I can order bearings that are ground and sold as a matching set in either "b
to b" or "f to f" that when mounted together and the retaining nut tightened
give a "light preload".

I can also order bearings that are not matched but are for "universal
pairing" that are about half the cost and are made to mount either way.
Some posts on the Yahoo Group mention that to apply a preload to these
bearings a shim is needed between them either on the inner or outer race,
others say none is needed. If the bearings are made to mount either way how
can they be preloaded without the use of a shim? If needed how thick should
it be?

If you do this without any shims the bearings will have way too much
clearance I suspect. What bridgeport used to do was to grind the face
of the bearing race to set this, rather than use shims, on the M heads.

My first take would be to order the same type (bb or ff) as the original
bearings, and purchase them as a true angular contact pair.

Jim


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