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Prop Pitch Wrench

To: <towertalk@contesting.com>
Subject: Prop Pitch Wrench
From: w9re@worldnet.att.net (Michael Wetzel)
Date: Mon, 20 Jan 1997 06:10:45 +0000
>On Fri, 17 Jan 1997, Phil Duff NA4M wrote:
>> 
>> How do I remove the aluminum shell that covers the motor?  I dont see 
>> any obvious fasteners for it on the outside other than what appears to
>> be a widely notched ring around the shell where it enters the gear case.
>> I tapped on it thinking it was perhaps a retaining ring holding the
>> shell but it didn't seem to want to unscrew and I didn't want to force
>> it unless I know thats whats holding the cover.
>
Frank Donovan W3LPL wrote

>The aluminum shell is held in place by screws around the periphery of the
>shell.  The shell may be a little snug, but it will come off!  The notched
>ring is a retainer that attaches the motor to the gearbox.  It screws out
>counter-clockwise and you can remove it by tapping firmly with a cold
>chisel.  A machinist friend fabricated a special tool for me that that
>slips over the motor and matches the notches perfectly.  It makes the job
>a little easier, but I used only a cold chisel and hammer for many years
>before that!  You may need to loosen this ring if the aluminum shell is
>binding against it, but the ring is not intended to retain the shell, only
>the motor.  After you have removed the retaining ring, the motor will pull
>straight out of the gearbox.

I too used the chisel method until one time I had a strange problem and I
kept having to take the aluminum shell off and on, and with the chisel, it
deformed the shell so much that I could barely get it back on. This
procedure was occurring on a tower at 32 degrees.  So I decided to find the
tool for the "spanner" nut.  It is called a "spanner wrench".  There are
several types (adjustable hook, adjustable face and adjustable pin, spanner
wrenches) the one that seems to work best on the prop pitch is the
"adjustable hook spanner".  The one I bought was for circle capacity 2" to
4-3/4".  It is available at Wholesale Tool 1-800-521-3420 for about $35.  

By the way the strange problem was a lead on a capacitor that after 15 years
in the air decided to short out to the aluminum shell,  took me several
trips to figure it out.

73-Mike W9RE


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