Grease or oil?

Some of the threads here got me thinking: What, in general, is a proper application for lubricating oil and when should one use grease?
I spent a fair bit on the web and am no wiser. Strong opinions abound, facts are difficult to come by. The nearest I got is: "If it is like a pin in a hole use oil, if the surfaces are sliding use grease". I thought lubrication is by definition for surfaces that slide in one fashion or another, so grease should be used for all?
Then there is the question of temperature range, molybdenum or not, etc. etc.
Furthermore, as far as I can tell the same game that manufacturers and retailers play with other chemicals (e.g. degreasers) is played with greases. Call it automotive grease you pay X, call it a "mil-spec gun grease" you pay 10X. And so on.
Any views here?
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Michael Koblic,
Campbell River, BC
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http://en.wikipedia.org/wiki/Grease_%28lubricant%29
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That is certainly a good article. Still, many people disagree what some of it means exactly. For instance in the gun community there are "greasers" and "non-greasers". Even there the application may differ for the same firearm depending on circumstances.
Many automotive manuals recommend use of two or three different kinds of grease for different parts. Many people have asked why this is necessary and in most of those cases I found the answers lacking.
Finally, there is the economic side of the issue, including manufacturers' claims which may or may not be true, but that is another matter...
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Michael Koblic,
Campbell River, BC
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Oil fast, grease slow?
A 3000 rpm spindle with 8" bearings uses grease. Kluber.
Now a 30K rpm grind spindle uses air mist oiling. Have a few of those at work. Bearings weigh in at 1.5 inches or so across the ball line.
Ways use oil and they are slow moving. Likely has something to do with evacuating debris. Tackifiers are added to keep surfaces wetted.
Guns, I use a teflon impregnated oil and clean when using in a dusty enviroment.
Oil tends to be constantly added to surfaces in continuous motion, grease tends to be a one time application for continuous motion.
Our big HMC's use thin oil for bearing lubrication and cooling.
Depends on the application.
If you want to try a tenacious grease, try coupling grease. Like honey on a cool day. Yuck.
Wes
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use oil unless it doesnt stay in place.
grease is oil mixed with a substance to give it more body. bentonite clay ground finely is used in some greases. others are described as oil mixed in mineral soaps.
use the manufacturer's recomendation. they've done the experimenting for you.
Stealth Pilot
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Clay seems like an abrasive to me.
Wes -- "Additionally as a security officer, I carry a gun to protect government officials but my life isn't worth protecting at home in their eyes." Dick Anthony Heller
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Most greases are oil and a metal soap. Usually lithium soap. Aluminum and sodium soaps are also used. Aluminum base greases are commonly used for "waterproof" greases. ERS
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Bentonite is usually used in wheel bearing grease, particularly wheels with disc brakes.
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Soap has been used also.
Bob Swinney
wrote:

Bentonite is usually used in wheel bearing grease, particularly wheels with disc brakes.
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Alan wrote:

As I recall, Bentonite physical characteristics is similar to graphite, sort of tiny flakes that when get wet become very slippy. So I would think with an oil to "wet" the material it would be "pretty greasy". :-) ...lew...
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wrote:

The amount of bentonite actually is pretty small, and it is laminar, so it slips somewhat like natural graphite (very *unlike* synthetic graphite). It's an effective thickening agent and it can take a lot of heat. Being a clay mineral, it doesn't melt like the metallic soaps used in most greases.
However, don't use it in places where other greases are recommended, unless you know what you're doing. The non-soap polymer greases usually are better lubricants. Bentonite greases are recommended in some heavy-duty industrial transmissions and similar applications. It's generally not very good for plain-journal bearings. It's better at lubricating gears.
At least, that's the way it was the last time I wrote about lubricants, which was....ummm...quite a while ago. d8-)
-- Ed Huntress
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