A large diameter machined billet aluminum
   prop shaft is only made possible by a major breakthrough in thin
 section bearings.

Paul Lamar


...ALSO ... with aluminum shaft and a "press-fit on the rotating member"
I cringe a bit.

I have no experience with press-fits onto aluminum.  I can just see the
bearing peeling off a layer of aluminum at assembly time and ruining
one's sizable $investment in the aluminum shaft.  You see any problems
in this?


Robin Bergland


Use a slip fit and Lock Tite Bearing Lock.

http://www.loctite.com/

Lock Tite is super glue basically.

I know of at least one Tracy PSRU that had silicon rubber locking the bearing to the housing. There is also a mechanical axial  lock consisting of a plate and a lot of screws.

The hybrid ceramic thin section bearing  has a steel inner and
outer race. As the shaft expands it locks the inner race of the bearing. If the aluminum housing expands it grows away from the outer race. In that case a flexible bond namely, red silicon rubber makes sense. The shear load on the outer race is minimal as that is what bearings do. Reduce the torque load caused by the bearing.

I know of another Tracy gear box case where a high pressure oil fed plain bearing failed to due to inadequate oil supply after working for many hours. The builder made the decision about the oil supply. Not Tracy's recommendation. Finally, under extra severe conditions, the bearing failed but it did not lock up until after the housing cooled.

Paul Lamar

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