[Beowulf] Re: What is the right lubricant for computer rack sliding rails?

[David Mathog]

Gus Correa <gus at ldeo.columbia.edu> wrote:
> 
> What is the right lubricant for computer rack sliding rails?
> Silicone, paraffin, graphite, WD-40, machine oil, grease, other?

If a set of rails isn't sticking, then I think "nothing" is the best
choice.  Rails generally don't get very much use, at worst going in and
out a couple of times a year.  That isn't going to wear off the
lubricant they ship with.  (Not sure what that substance is, but it
feels almost like vaseline, so probably it is a very light grease.)

If a set is sticking you might try a very small application of lithium
grease, run the sliders in and out until the action is smooth, and then
wipe off any excess.  Lithium grease probably isn't ideal for ball
bearings as it is a bit thick, but it is readily available, isn't very
volatile, and likely won't dry out over the life of the system.  A
lighter grease might be better, the stuff they use to lube guns should
be good, but unless you keep guns you probably won't have any of it around.

Oil might work but it tends to stink and drip.  Similarly, WD-40 is not
a good choice.  WD40 is very volatile and is a better grease cleaner
than it is a lubricant.  WD40 would definitely unstick a stuck slide,
and would lube it for a while, but then it would evaporate, and the
slider would likely stick even worse than before.  WD40 is volatile
enough that it might create a blast danger as it cycles in the
evaporated state around and around a machine room.  

Regards,

David Mathog
mathog at caltech.edu
Manager, Sequence Analysis Facility, Biology Division, Caltech