[TowerTalk] Worm Gears

Robert Harmon k6uj at pacbell.net
Thu Jul 2 00:37:55 EDT 2015


Matt,


The original question was which Mobil 1LS, 75W90 or 75W140 is correct for Hub City worm gears.

The answer is neither one.  The gear lube recommended by Hub City is specifically formulated for worms gears and these two lubes are not.  

Giving us an astute comparison between the viscosity indexes of the two different types of lubes is needless.
We don't need to know how the PAG viscosity converts to the ISO system. It might be interesting from an engineering
perspective but is irrelevant in this discussion.  

The Hub City worm gear application sheet spells out their recommendation and thats
all we need to know.  

Bob
K6UJ





In summary my point was that 
> On Jul 1, 2015, at 8:24 PM, Matt <maflukey at gmail.com> wrote:
> 
> Thank Bob,
> 
> Concur.   But your question was choosing between 75W90 and 75W140, which are
> grades of differing viscosity indices rated under the SAE system.   Hub city
> lubrication guide recommends PAG 460, which is an ISO grade.   In the ISO
> system, "PAG" specifies the formulation (PolyGlycol) and "460" specifies the
> viscosity index.    The viscosity index of 75W140 under the SAE system more
> closely matches the viscosity index of 460 under the ISO system. 
> 
> Good Luck on your project!
> 
> P.S.  Take a look at my WEB site
> http://192.185.4.60/~flukey/km5vi/New%20Station/Tower%20Prep/Tower%20Prep.ph
> p
> to see a photo of what happens when the wrong lubricant in a Hub City box.
> The former owner (bless his heart - now a SK) of this box replaced the vent
> cap on top of the housing with a grease zerk and pumped it full of axle
> grease!   I surmise because the seals were so far gone that he probably
> would not have been able to keep any gear oil in it.   Being an older box
> with needle bearings (the new designs use tapered rollers), the bearings
> essentially disintegrated.  the shafts and gears were actually still in
> pretty good shape.
> 
> KM5VI
> Matt Flukinger, P.E.
> 
> 
> -----Original Message-----
> From: TowerTalk [mailto:towertalk-bounces at contesting.com] On Behalf Of
> Robert Harmon
> Sent: Wednesday, July 01, 2015 8:55 PM
> To: towertalk
> Subject: Re: [TowerTalk] Worm Gears
> 
> Matt,
> 
> The viscosity is only part of the equation.
> I might be a comparable viscosity but there are many other ingredients that
> are formulated into the lubricants for specific applications. 
> The gear lube we are discussing is a synthetic lube specifically formulated
> for worm gears.
> 
> Bob
> K6UJ
> 
> 
> 
>> On Jul 1, 2015, at 4:06 PM, Matt <maflukey at gmail.com> wrote:
>> 
>> Hi Rick,
>> 
>> Viscosity of ISO 460 converts to SAE 140, 75W140.
>> 
>> Matt
>> KM5VI
>> 
>> -----Original Message-----
>> From: TowerTalk [mailto:towertalk-bounces at contesting.com] On Behalf Of 
>> Richard (Rick) Karlquist
>> Sent: Wednesday, July 01, 2015 4:52 PM
>> To: Robert Harmon; TowerTalk at contesting.com
>> Subject: Re: [TowerTalk] Worm Gears
>> 
>> 
>> 
>> On 6/30/2015 3:52 PM, Robert Harmon wrote:
>>> I dont want sabotage our worm gear discussion but wanted to throw in a
>>> question about gear lube for a worm gear box.    I am going to change the
>> gear oil in my US tower
>>> box.  It is a Hub City worm gear.  Thinking of using a Mobil 1 
>>> Synthetic
>> gear lube,  a PAG type.
>>> Dont ask me what the PAG means but Hub City recomends a PAG synthetic.  
>>> Any one used a synthetic ?
>>> 
>>> Bob
>>> K6UJ
>>> 
>> 
>> Mobil 1 LS comes in 75W90 and 75W140.  Which is correct for Hub City?  
>> Is 1 quart enough for a gear box?
>> 
>> Rick N6RK
>> _______________________________________________
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