[R-390] More geartrain rebuild info

[Bob Camp]

Hi

I very much agree that a gear train with a reasonable amount of crud in 
it probably will require the planetary gears be torn down. When you do 
the only way to really get them clean is to take them down to pieces 
and clean each one.

The obvious gotcha is how do I get these back together with only two 
hands and a limited number of toes involved. Cleverly bent paper clips 
seem to be the "other" way to do this if you don't have access to stuff 
like plastic hemostats.

Here's an issue that's a little more subtle. The gears probably left 
the factory all nice and uniform. When they did you could swap any 
"top" with any "bottom" and there would be no net effect at all. Over 
the years each "top" has rubbed against it's respective "bottom" for a 
really long time. Essentially you have created matched pairs of gear 
halves.

So in addition to needing a number of fingers and toes to put it all 
back together you also need three sets of eyes to make sure all the 
sets remain with each other.

The gear will work pretty darn well even if you randomize the gears. My 
story is that it was a controlled experiment and I'm sticking to it. If 
you want a silky smooth gear set when you are done it seems to be best 
to keep everything in order ....

	Enjoy!

		Bob Camp
		KB8TQ



On Feb 23, 2005, at 10:19 PM, Barry wrote:

> List,
>
> In the process of tearing down this geartrain, I noticed the planetary 
> gears
> were quite clogged with grease.  Scott's slide show says it probably 
> isn't
> necessary to tear the planetary gears apart, but it didn't appear I 
> would
> get this one clean unless I did and I'm sure glad I did.
>
> Upon taking apart the three split gears, all three exhibited a fair 
> amount
> of drag when I twisted them against each other.  Upon closer 
> inspection, I
> could see small burrs on the teeth.  After removing these burrs, the 
> gears
> ride smoothly against each other.  I would never have known this 
> unless I
> disassembled them.  Also, it gives me a good chance to ensure a lot of 
> the
> hardened grease and dirt is removed.  After a 24-hour soaking in 
> kerosene,
> there was still a significant amount of grime in this assembly.
>
> Now if I can figure out how to get four split gears all tensioned and
> reassembled at the same time!
>
> Barry(III) - N4BUQ
>
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