practical lubricity

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.

I use this stuff for locks and clockwork indicators called "TRI-FLOW". I know that Teflon oils seem to be all hype but the stuff actually works better than any other oil I've used for locks. Doesn't gum up the locks and penetrates well. Maybe it will also help with the static friction problem you have. Stiction is a problem with some mechanical measuring instruments I use in the machine shop because they get oil on them and gum up. Clock oil doesn't work as well as Tri-Flow does for these tools. I think it's because the solvent in the stuff allows it to penetrate better and the residue left behind isn't very tacky. Eric

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Interesting thought.

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

Thanks for the suggestion. I'll look for it.

By the way, I neglected to mention that the ball-and-socket is plastic, with a metal band in the socket.

I think you mean something like corn starch.

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.

Then I'd be careful using my suggestion because the solvent in the stuff may attack the plastic. I assumed metal parts. There is some other stuff I use on rubber parts, like the window gaskets in my car and truck. It's a dry lube made by, I think, Borden. Anyway it's some type of white looking powder suspended or dissolved in some type of fast drying liquid or solvent and comes in a spray can. I sprayed the stuff on the rubber gaskets and now the windows go up and down much easier. Of course it also may attack the plastic. Eric

"If it's Borden... it's got to be good."

I've also thought of using graphite powder.

What he said... Assume you've tried the obvious technique of applying rotation to the ball joint while implementating the desired translation?

Of course. The socket is designed for tightness at the expense of ease of movement.

And you want to defeat that design objective that keeps the device stable under vibration.

Wrong assumption. You're assuming that making the joint easier to move smoothly will necessarily cause it to change position under normal use. My Focus does not vibrate, except on rough road.

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I would try locksmith's dry lubricant - ground graphite or talcum powder , at least no solvents going to attack the plastic

The old slide rule trick is to loosen with graphite and tighten with chalk dust.

Cheers

Phil Hobbs

I used to carry a mini tube of Vaseline to lube my slide rule.