Finn,
Does your Ross gear box look like this?
You never know.

If so perhaps you could put a 1/2 AL plate in front
of the seal between part 3 and part 11 to take the
thrust bearing load and make a new 1/2 inch longer shaft.
You would also need longer studs or bolts to hold
the whole thing together.

Paul Lamar

A good idea if I needed a new shaft anyway. One problem is it leaves very
little space for the thrust bearing and pin, only 13mm (unless I counterbore
into the plate). The thrust bearing Tracy is using is 12 mm thick, leaving no
space for the pin. I wish I knew how thin that pin can be and minimum edge
distance from pin to planet gear teeth and from pin to thrust bearing. I'd
also like to know how much force the bearing applies to the plate (how thin I
can make it).

Finn

Much better.

Paul, I really like your idea above. If I use a 4mm thick thrust bearing (with
1.44" or 1.5" ID) and a 1/4" plate and a 1/4" pin, I could use the existing shaft
(would reduce spline engagement from 7/8" to 5/8") which machining required on
neither shaft nor thrust plate. I would mount the seal (with a smaller 1.44" ID in
the existing bulkhead counter bore - hopefully I can find a seal with 2.75" OD).

It raises these questions for educated guesses:

What happens if I use a 1.5" ID thrust bearing on a 1.44" shaft?
Would a 1/4" pin be big enough (currently use 3/8")?
Would .05" pin-planetgear clearance and .05" pin-thrust washer wall be sufficient?
Would 5/8" spline engagement be sufficient?
How often would I have to replace the thrust needle bearing (2 mm - 0.0787" D
needles)?
(I'm looking at a Torrington NTA-2435 assembly and two 1 mm race washers.)

I might be able to use an even thinner thrust plate. Maybe use steel instead of
alu?
Bulkhead center hole is 2.75"
Race washer ID: 1.5"
Race washer OD: 2.187"
Approx .5" from center of race to bulkhead hole edge.
Transferring 1200 pounds around a 8.6" circumference (4.3" sq in) and allowing for
maybe .0005" flex over .5", how thick does the plate need to be. In 2024 Alu? In
steel? God, I wish I were a mechanical engineer!

I could live with replacing a $5 needle bearing every 100 or 200 hours. I would
want to inspect the gears that often anyway.

Finn

It is hard for me to follow this.

Choose one of these drawings #1, #2 or #3 that look most like your
Ross and give me the following dimensions.

A:
B:
C:
D:
E:

Paul Lamar
 
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