In article , Gunner Asch says...

Hardinge spindle bearings btw..are angular contact..and are mounted
with a preload cylinder between them. In the case of many or most
ballscrew thrust bearings with single end cartridges...they are inner
race to race as the pre-load cylinder.

Early Hardinges used 3 bearings..but all later ones..after the 1940s,
only used just the two, in th at configuration.

I think my ESM-59 is post 40s, and it did come with three bearings.

The first two of course are the angular contact pairs and take the
radial and axial loads, the remaining one at the rear of the spindle
is floating in the bore and takes only the pure radial loads of the
end of the spindle.

Jim Schwitters was kind enough to send me a copy of hardinge's breakdown
and replacement instructions for that machine - their nomenclature
for the headstock was "Type R" for what it's worth.

Apparently the HLVHs use the two angular contact pairs with preload
cylinder - likewise the DV59s?

So apparently hardinge went through the following design changes:

From collapsing cast iron shell bearings (on the cataract lathes)
to three bearing setup (starting with the BB headstocks) and then
at some time to two bearing setups after the 40s.

It would be interesting to talk to the engineers who decided how
and when to make those changes.

Jim


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