Worm Gear Oil

I had a simliar problem 10 years ago and we changed over to Mobilgear SHC 460 for our worm gears and have had great success.

Do you know the viscosity or the AGMA it is?

Kesco,
Mobilgear SHC 460 is an ISO 460 synthetic (PAO)which converts to AGMA 7

Clyde Hughes, MLT I, MLA I&II

Noria Field Services

We also use Mobil SHC 460 for our worm gears, and it works great, but in our H1 food grade areas, we use Mobil Gargoyle SHC 234, which is also an ISO 460. It works almost as good.

Just curious. On the oil spec for your gearbox, does it call out for an AGMA 7, or AGMA 7C, or AGMA 8 or AGMA 8C? C means it's compounded, specifically for types of worm gears.

Hey Kesco, call American Agip in Westbury NY and order worm gear oil. Our company provides it in all the applicable vis grades.

whatever you do, choose a gear oil that doesn't contain sulfur, which is corrosive to yellow metals commonly found in worm gears, and, in your case, one that has a good dose of foam inhibitor. mobilgear shc is just one example of non-ep gear oils. chevron's product is called hipersyn and is available in all iso grades as well. just find a dependable supplier.

Does anyone know if molly (molybdenum disulfide) has a problem with yellow metal wormgears?

There used to be and maybe still is a company that used moly in all there gear lubes, can't remember the name though. Anyway I don't believe moly will affect brass etc directly. However, moly tends to build on itself and overtime can affect close tolerences, that shouldn't be a problem in worm gears though. Having said that, you could run into a problem as moly can't tolerate hydrocloric or nitric acid contamination and these are chemicals often found in lubricant enviorments, especially where heat, water and air are present :-) At air temperatures above 650 F molybdenum disulfide will oxidize to form molybdenum trioxdide, which is abrasive.

Hi,
I also remember coming across some info that said that Moly will cause ball bearings to "skate" and to stop rolling.

my 2 cents on moly. There is another form of moly that is completely oil-soluble (actually part of the oil) and will never settle or build up on itself. Primrose Oil Co. manufactures many products with its proprietary Moly-D additive, which instead of being a solid additive, is a liquid form of moly and thus becomes part of the oil. It is used in gear oils, hydraulics, greases and has been proven superior to the solid form of moly. I know of no reason to suspect moly as contributing to copper/brass problems.

The slippage may be a reason of coeffienct of friction of the gear oils which will prohibit self locking of worm gears.
The additive package, in some high performance gear oils reduces the co efficient of friction too much and hence self locking is effected- it may be moly-liquid molly or others as well.
So we need to look at the SRV values of both the previous lube as well as the current lube to get an idea.
If the previous one had a high SRV Value pl shift to the same SRV value and hope fully the problem will be arrested.
Could you pl specify the brands of oils -the previous and the cuurent.
Your current oil suplier should be able to help you in getting the SRV VALUE.
There can be several reasons for foam may be mechanical to oil.
To get rid off the foam, if urgent add a bit of anti foam or you need to lok at what mechanical correction has been done and proper viscossity is maintained or not.

Arupanjan Mukherji

Picking up a different new gear oil of similar or the same viscosity as the used oil and expecting to work without any problem is as sure thing as scoring by throwing a Hail Mary pass.
Every time in such situation one must be sure that these oils are compatible (evaluated by ASTM D 7155), and flush the system before introducing new oil. Mentioned foaming issue led me to believe that neither of those two things have been done. Base oils (if one of them is not PAG) are in general compatible, but additives in those oils may not be. Also, visual observation of compatibility/incompatibility (ASTM D 7155 Tier 1) could be done by the personnel at the site. It is not a rocket science to do it, and is absolutely better than trusting on word from a guy that has direct interest in selling you new oil. This process (testing compatibility and flushing) are the basic stuff and should be followed with oils in nearly all equipment/machinery applications.