On Thu, 1 Dec 2005 13:52:36 -0500, Ned Simmons
wrote:

In article ,
"Terry Keeley" tkee(no spam)@(or mail)rogers.com says...
I'm restoring my 1963 Clausing 8520 mill ( pictures here if interested
http://gallery.intlwaters.com/thumbnails.php?album=323 )
and in the process am replacing the spindle bearings. I've read through
many posts on the Yahoo Group and have just gotten more confused.
Talked to a few bearing "engineers" (ya right) at SKF and they don't seem to
have solid answers either.

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"?

Almost certainly back to back.


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?

You'll have to ask the bearing mfr for a definitive answer
on the spacer thickness, but I wouldn't recommend this
approach. A few tenths will make a big difference in the
preload, possibly resulting in overheating or loss of
rigidity, depending on whether the shim is too thick or too
thin. Best to buy the proper matching set of bearings. A
matched pair of precision 7207s should cost you around
$275.

Ned Simmons


Call Alpine Bearing in Boston. Ask for JC..get his quote before buying
from anyone else.

Gunner

"Pax Americana is a philosophy. Hardly an empire.
Making sure other people play nice and dont kill each other (and us)
off in job lots is hardly empire building, particularly when you give
them self determination under "play nice" rules.

Think of it as having your older brother knock the **** out of you
for torturing the cat." Gunner