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Re: [TowerTalk] Very Old Grease Characteristics

To: Pat Barthelow <aa6eg@hotmail.com>
Subject: Re: [TowerTalk] Very Old Grease Characteristics
From: "John." <johne@tds.net>
Date: Wed, 20 Dec 2006 21:46:57 -0600
List-post: <mailto:towertalk@contesting.com>
We in the past with similar type of assembly used a "Port a power" 
hydraulic pump.
We removed the pushing piston from the hose end and used the hydraulic pump
end screwed  the hose into the threads of the removed grease Zerk.

http://www.northerntool.com/webapp/wcs/stores/servlet/product_6970_491_491

The idea is to use hydraulic   pressure from the port a power to loosen 
the old grease .

You may also fill the hose with solvent, Then the "Port a power" will 
push the solvent around the pin.

Be very carefull !~

de John KØCQW



Pat Barthelow wrote:

>Folks:
>
>We are stymied in our work to bring the Jamesburg 30 meter dish back into 
>operation.  The dish is currently in the "stowed" position, pointing 
>straight up.  It is locked in that position by a 3" diameter stainless steel 
>"pin" that is electrically driven up a cylinder, into a hole in the heavy 
>steel elevation motion  system.
>
>See: http://www.longandflatsociety.com/Default.aspx?tabid=474
>
>The pin's  close fitting cylinder-housing has zerk fittings for heavy grease 
>liube that probably had not been attended to in years, possibly decades.  
>The dish probably had not been the stow position for  decades, if ever, as, 
>it sat pointed at an Intelsat geosynchronous satellte, low to the horizon, 
>over the Pacific since 1968.   Two years ago, someone moved the dish to stow 
>position.  We, wanting to do moonbounce with the dish, have tried the two 
>ways to retract the pin to unlock the vertical motion, using the locking pin 
>motor drive, and the manual  crank, with no luck. We have hand cranked the 
>vertical motion support so as to remove any shear forces on the pin;  That 
>is, the pin is precisely centered in the close fitting  hole.   The pin is 
>so solidly stuck, it may as well have been epoxied into place.  Moderately 
>powerful forces have been used to try to push the pin down out of the locked 
>postion. to no avail.
>Some of us think there may be wear ridges inside the cylinder preventing pin 
>movement downward.   The pin is in some ways similar to a piston,  has a 
>connecting rod and wrist pin-like connection in its bottom for motorized 
>retractor/inserter drive.
>We are going to investigate that for possible cylinder interference,  in 
>detail our next visit.
>
>Others think that the 30 year old grease has fossilized to something akin to 
>epoxy, or coax seal,  and is keeping the pin from moving.
>
>My question is what does thick bearing grease evolve to in, say 30 years, if 
>untouched?   Stone?  Epoxy?   Grit?
>
>A parallel to normal towers might be a tower in decades long storage, that 
>had heavy greased cable pulleys.  Has anyone found 30 year old pulleys to be 
>jammed up hard with what used to be lube grease?
>
>73, DX, de Pat AA6EG aa6eg@hotmail.com;
>Skype: Sparky599
>Moon or Bust!--Jamesburg Gang Rides Again!
>
>
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