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Caveat: these are scanned pictures from several years ago.  I'm not a mechanical engineer so some of the terms used below may not be 100% accurate but hopefully describe the pieces adequately.

The prop pitch motor was manufactured by various companies in the 40's.  One of the companies was Curtis Wright.  It is an engineering marvel with a gear reduction scheme of 9600:1.  I've put an indicator on the output shaft and turned the motor shaft with my fingers and have seen the indicator move back and forth showing how tight the unit is.  The bearings and oil seals are standard and available (except for upper planetary gear reducer).  Through the years I've used various lubrication schemes, synthetic oil, antifreeze, SAE #10 to name a few.  Lately I've been using a low temperature grease.  My father at one time was trying to figure out how to use an oil pump to bring the oil back to the top of the unit from the bottom (since original configuration was horizontal and I've always used them vertically).

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These pictures show a prop pitch motor in exploded views.

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These pictures show the top bearing and oil seal used with the bevel gear (some have discarded this gear).

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Various parts laid out.

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Bottom housing showing wire leads.

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Lower and upper planetary gear reducers.

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Top and bottom housings.

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Miscellaneous pictures.

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Gears and lower planetary carrier.

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Lower planetary and a top of a modified prop pitch for faster rotation (don't do it)(bevel gear not used).  When you do this modification you cannot return to the original design when you need the slower rotation for a larger array.

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Top bevel gear and two motors (different styles).

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Some common bearings used and the large oil seal.

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Shown is a bevel gear that a stub is usually welded to and used for an output shaft.  This gear along with the bearing above and a plate (that comes on some prop pitch units) can serve as a rotator mounting plate with the advantage of being able to remove the motor and still support the mast/antenna in the tower.

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Motor leads and brushes.

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Motor rotor and armature.

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Two different style armatures/rotors (both small motors).

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Upper planetary gear reducer (bearings not available).