Ed, here is that PSRU gear data.

Paul Lamar



I had a whole hour to think, while driving back from Ventura, about the
idea of cutting the planet cage onto one end of the prop shaft. Can't
think of any good reason why we should not do that. I think the od of
the 7075 shaft material we intended to use for the steel planet may be
slightly too small.The only added issue is the potential need for longer
planet shafts to give them greater depth in the alum cage/shaft. I guess
that means I can use the 6 planet gears from the unit I left with you
today and forget about doing the edm or finding special bolts.

The center shaft (pn#675 Makco) you had in your box could be used for
the link to the modified forward drum. This will make getting parts
simple because they all come from the same source. What we might do is
machine the teeth down to our preferred od of the small end of the sun
gear in order to slip a steel tube over it, and use a smaller tube to
slip into the id of the same sun gear. This way the sun gear is slipped
in between the two tubes thereby doubling the shear strength of the hold
pins; while also lowering weight. The two tubes would be welded to the
trimmed end of the modified center shaft.

Ed Carver

Better get a quote on the job first. The planet shafts are not easy
or cheap.

Paul Lamar



I might have a couple thing going for me on this. The planets apparently
have different shaft sizes for different trannys. I need to learn which
size might be most readily available. How should I go about getting the
pins out of the planet shafts so the shafts can be precisely measured?
Screw a tap into them and pull them?

Ed Carver


So far all the front planets I have all have the same .440 shafts
more or less. There is room for a 5/16 EDM.

The area of a 5/16th bolt is .0767 so max clamping load per bolt is
7,670 pounds. 46,020 pounds total for six. Using Murray's statement
about the clamping load doing all the coupling and figuring a coeff.
of friction of only .1. the outer 1/2 inch width  of the planet 4
inch diameter carrier is about six square inches. That would give a
torque of about 4,600 x 2 or 9200 inch pounds or 766 foot pounds. No
help from bolt shear.

Steel on steel coef. of friction is actually higher than .1. As I
recall for locomotives it is about .7 so we might be looking at as
much as 5360 foot pounds.

In addition Grade 8 bolts have a proof load of 120,000 psi and not
100,000 so there is another 20%. No help from bolt shear.


Paul Lamar


I've sort of assumed we would use grade 12 or better. I believe rod
bolts are at least that. If I have any worry about bolting, it is
preventing them from backing out, or pulling the alum threads out. I can
see using the nord lock fastening system to solve that problem, and
wiring with loctite, plus maybe thread inserts in the alum shaft. A lot
depends on how hot it will all get.

Ed Carver

Drilled heads and safety wire. If you can find shafts and afford an
integral aluminum planet carrier that would be a real cool solution.
We need to figure out how to retain the shafts without the roll pins
so it can be repaired.

Paul Lamar


The alum front planet you have has larger shafts. I want to know their
diameter. These may be necessary for an alum cage. Also, if you have an
alum rear planet, send the dia for those too. And, what is the dia of
the alum planet cages?

These cages are likely cut on a mill with a precisely sized large dia
cutter, then drilled for the shafts. Are the alum cages a casting?
Looked to me like they were.

Ed Carver


I don't know for sure but they look like a dia casting.
Certainly not sand cast.

You will see a message shortly on the integral aluminum cage.

George's method of adding six bolts between the planet gears has a problem with the oiling holes.

Getting the roll pins out is a real problem for replacing the planet shafts with a special hardened and ground bolt/planet-shaft.

I think a hypodermic needle and high pressure oil might work.
Put the needle all they way down in the bottom and apply a shot
of high pressure oil to the needle. In theory it should pop out some
what.

I also thought about tapping  it with a 2-56 tap.

Then there is supper glue and welding wire but you have to get all
the oil out first.

Here is another idea. Stick welding wire in and apply a lot of current.
The welding wire might then weld itself to the roll pin. Then pull it out. This trick might work the best and is easy to try on the junk planet carrier I have. Are you up for this test Ed?

Paul Lamar