On Sun, 13 Nov 2011 09:43:07 -0800, "William Sommerwerck"
wrote:

"Jeff Liebermann" wrote in message
.. .
On Sun, 13 Nov 2011 08:30:07 -0800, "William Sommerwerck"
wrote:

The car holder for my GPS navigation system uses a ball-and-socket joint.
It
holds the unit without any slipping -- but no matter how much I fuss with
it, I can never get it into exactly the position I want. There's simply
too
much friction, both static and moving.

've tried silicone spray lube, but it doesn't do much good. I've thought
of
ithium grease, but... Nah.
Any suggestions?

Nope. If you do find a suitable lubricant, there won't be enough
friction to hold it in place when the car bounces down the road. I
think taking the ball and socket apart, and cleaning or polishing the
mechanism, will probably work better. If you must lubricate the
plastic, I suggest something dry, such as talcum powder.

Interesting thought.
One can imagine a thixotropic lubricant -- though whether any exists...

I think you mean something like corn starch.
http://en.wikipedia.org/wiki/Non-Newtonian_fluid
It won't work because you can't maintain much pressure on the fluid
with thin plastic parts. Eventually, the plastic will creep, the
pressure will be relieved, the lubricants viscosity drops, and your
map display falls over.

I've used talcum powder for various unconventional lubricating
applications. Out of the bottle, the particles are rounded. However,
pressure is applied, they flatten, creating addition friction. When
applied to your ball and socket, it will initially act as a roller
lube. When you apply pressure, it almost becomes an abrasive (without
defacing the plastic surface. The problem is that there's no
resiliance. Once you clamp down on the powder, it's permanent. If
you miss, and have to move it later, you might as well tear it apart
and apply a fresh load of talcum powder. The right stuff might be
tiny rubber balls, but I don't know where to get those (or make them).
Maybe try some pink eraser dust or shavings.


--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558