"Ned Simmons" wrote in message ...
On Mon, 12 Mar 2012 12:29:28 -0700, "PrecisionmachinisT"
wrote:


Okay great....now I need to let you know that my discription above was
incomplete almost to the point of being totally wrong.

In the case of the above face /face installation, IF a UNIVERSAL set is used
then you would also need to place a thin shim in between the pair of inner
races--only THEN can you add preload by setting them into a shallower cavity
in the quill cartidge or housing...alternatively, with a back-back set, you
would add a shim between the outer races instead...

Precision angular contact bearing pairs almost always come with a
predetermined preload, controlled by grinding an offset in the mating
faces of the races. Flush ground bearings are available, but they're
the exception for the type of bearing we're talking about here.


In practice, there is usually a inner and an outer steel spacer thats placed
in between the bearing sets and they range in height anywheres from say
about 1/2in thick for a r8 spindle on up to about 4in thick where you have
60 taper....

At any rate, either they are the exact same height or else one of them is
say .0007 or so thinner than the other--you can surface grind these as a
set if you have a surface grinder, what you do is you take them both to a
cleanup and then you remove one of them and continue grinding the other (
which one to remove depends upon whether the actual set you are installing
is universal, back-back or face-face )

I'd be very cautious about doing this without knowing the specifics of
the bearings and spindle. As I said in above, in the great majority of
cases the bearings are ground as a set to the desired preload. The
spacers are identical in length.


Yes "most" common these days are duplex universal and they are intended for face-face mounting.

Emphasis on "most".