Posted by george on October 25, 2004 at 20:38:05:
In Reply to: Re: Help with old standard posted by David Robinson on October 25, 2004 at 11:32:46:
Thanks Mr. Smarty (LOL). We can always check to see who is in fact older!
I guess I didn't state my original question correctly, or clearly enough.
What we have is the original 1905 spec was simply 14P. No PA was specified. My guess, and what I was trying to clarify was, by default and due to the year was this a 14-1/2?
To make matters worse, we've done some more research on the engineering change records, and it gets even more whacky. (see mixed angles post).
The ring gear was NEVER changed from 36T 14P (the 1905 spec without stated PA)for its entire life.
The sun gear which was 1" OD, was originally 12T 14P (No PA specified) A revision 15 yrs later, took this to 14P, cut to 18P depth, 20 degree.
The planet gears were originally 12T, 14P (No PA specified) and 1" OD. The revision in the 15th year was to take these to .969 OD, 14P cut to 18P depth, and 20 degree PA, to match the revised Sun.
Sounds strange but they apparently ran this combo until the end of production, and there are literally tens of thousands of these pups still running today.
I was curious to know that if no specification on PA was made, circa 1905, what was the default PA?
And more curiously, do any of our gear 'experts' have comments on that final gear revision mix? One, we're trying to figure out why they would ever do it that way. Two, it would have been a simple matter to also revise the ring gear, it wasn't that expensive a part. Our guess and it's only a guess is that A, there was a rogue engineer who got his toots out of such a thing, or B, they had a brilliant engineer who figured that since the the sun and planet could be replaced easily, and the ring needed total disassembly of the device, and since the ring gears never showed ANY wear, be had a backwards compatible design improvement. (Still doesn't answer why new production after the rev. date used the old ring gear spec)
Thanks for your response
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