Re: Ball screw / ball bearing lubrication?

Wow, great response - thanks!

I realized after I wrote my message that I should have looked on the
manufacturer's web sites first, but the notion came too late. I have
a bunch of white lithium grease I've been using on almost everything
else, so I guess I'll use that on my screws. What do you mean by
a "30%" grease pack? 30% grease and 70% something else?

Thanks,

Jeff

--- In CAD_CAM_EDM_DRO@y..., "Les Watts" <leswatts@r...> wrote:
> Jeff,
>
> The short answer is yes.
>
> Most any ball bearing device has more that point contact
> between the bearing and race due to the material's elasticity.
> There is some scuffing so a lubrication film is needed.
>
> Specific lube recomendations can be had by looking at
> manufacturer's data. A quick search will prob yield some
> information right on the net.
>
> I can give some general guidelines though.
>
> Ballscrews are relatively low speed devices and are usually
> grease lubed. A straight petroleum based grease is usually
> fine. EP can be used but is not required. Lithium grease has
> good water resistance; sodium has somewhat better rust
> prevention (it can absorb water).
>
> If the ballscrew is is used hard and has high preload oil
> lube may be used. The oil has an important secondary function
> of acting as a coolant.
>
> Oil is sometimes better in a dirty environment as it can be
delivered in a
> way that the screw is cleaned.
>
> But.... oil delivery systems cost money!
>
> For angular contact....
> At low speeds a 30% grease pack is often used. Too much
> grease will cause churning and overheating.
> Automotive wheel bearing grease is fine.
>
> At high speeds oil is used, but it depends on the bearing
> and application. Usually much above 10,000 rpm is in the
> outer limits for grease. Some examples of grease in high
> speed bearings can be seen such as wood router bearings
> at up to 25,000 rpm. Their life is much much shorter as a
> result. Other longer lived high speed angular contact bearings
> are oil mist lubricated and can last a very long time.
>
> Leslie Watts
> L M Watts Furniture
> Tiger, Georgia USA
> http://www.rabun.net/~leswatts/wattsfurniturewp.html
> ----- Original Message -----
> From: "jeffswayze" <jswayze@o...>
> To: <CAD_CAM_EDM_DRO@y...>
> Sent: Tuesday, January 29, 2002 8:53 AM
> Subject: [CAD_CAM_EDM_DRO] Ball screw / ball bearing lubrication?
>
>
> > Here's a simple question for those more experienced than myself:
> >
> > Are ballscrews/ballnuts supposed to be lubricated in some way?
> >
> > What about ball bearings (angular contact bearings in particular)?
> >
> > -Jeff