> > Ken Welter wrote:

 > >
 > >    Been thinking about it and I think that following the Ross design
 > > of mounting the planet solid on the prop shaft, the problem is that
 > > any play at all will result in uneven loading on the gears and even
 > > with needle roller bearings there is going to be a bit.
 > >   Why not spline the prop shaft and and slip the planet on as it was
 > > designed and leave it unmodified so that there is a bit of float in
 > > it.
 > >   Also I think this may be easier to incorporate into the hollow prop
 > > shaft design that you have mentioned Paul.
 >
 > >   Another advantage to this is easy replacement just slip it out and
 > > slip in a new one and a friend that works a trany shop said that he
 > > would buy good used ones from me for half price of new so I would
 > > lean to replacing them every hundred hrs or so just for piece of
 > > mind, I cant believe how cheep these planet sets are as I have found
 > > the new six pinions for $68.
 > >
 > >    Ken
 >
 > The stress goes up as the diameter goes down to accommodate a spline.
 >
 > The stress for solid shafts are proportional to the fourth power of the
 radius.
 > That means roughly a one inch radius shaft to the fourth power is just one
 but
 > two inch radius shaft to the fourth power is sixteen or sixteen times
 stronger!
 > Count em... SIXTEEN TIMES STRONGER!  Now for a four inch HOLLOW shaft
 > compared to a 2 inch solid shaft it is not quite this good but it is
 > in the same ball park.
 >
 > This is why I suggest making the inner end of the
 > hollow shaft the same diameter as the shaft circle of the planet carrier.
 > It is load path analysis. The load path length is minimized.
 > That leads to the lightest weight design. The load comes right out
 > of the pinion shafts right into the large hollow prop shaft.
 > There is little load on the planet carrier itself in this design.
 > All it does now is mainly hold the pinion gears in alignment.
 >
 > If there is any slop in the prop shaft needle bearings the planetary gears
 will
 > self center anyway. Best to precision machine the whole thing.
 >
 > Any slop in the heavily loaded spline will lead to excess wear in the
 spline.
 > Just another spline to add overall  torsional slop.
 >
 > Same goes for the prop end. It makes no sense to go down to a 1.25 inch
 > diameter prop shaft and then back out to a 5.5 inch diameter prop bolt
 > circle. The torsional and bending stresses are much much higher in
 > a 1.25 inch shaft than they are in a 5.5 inch shaft.
 >
 > Same goes for the ring gear. Don't use a ring gear bulkhead with splines.
 > Lock the ring gear to the housing with six set screws screwed into
 > taped holes in the housing. That maximizes the diameter of the
 > ring gear fixing device minimizing the stresses.
 >
 > Paul Lamar

 Ken,
 Slausons has regular specials on just about everything - I just ordered 3
 NEW 2.85 planetarys at $38 each, their regular price is only $63- $68.
 The 2.17 is double that price for some unknown reason, but I will find out -
 tell Luke I sent you and you want the right price.
 I don't know if the special is still on, but you could ask!
 George (down under)

   Yes Paul I agree on all those numbers and I am seriously looking at
the hollow shaft but there are some drawbacks as the OD of the
bearings are going to be 5 inch with a 4 inch shaft and I think that
any saving on shaft weight will be offset buy the size and weight of
the bearings and housing that it takes to carry them, also the seal
is going to be huge and my experience with large seals is that they
tend to be leaking bastards and tend to wear out faster do to the
high surface speeds.
  If I go for the hollow shaft I think I would bolt the planet on as
you say but if I go for the solid shaft I think I would use the
spline, I don't like the extra slop as you mentioned but I am not to
worried about it braking or wearing out as that aluminum planet seems
to hold up against the 460 Ford just fine which amazes me and the
steel should be better, besides we are running with that spline on
the damper without any problems which is amazing without any lube on
it.

  Thanks George for the info on Slauson, I need the 3.17 set right now
but for that price I may pick up on a 2.85 set to mess with in the
future.

    Ken

 
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