N_Cook wrote in message
...
Jeff Liebermann wrote in message
...
On Wed, 10 Aug 2011 08:17:53 +0100, "N_Cook"
wrote:

A job for tomorrow is to take some measurements of one of those tiny
preset
size pots.
The wiper arcs are something like 3 off 10mm long , and section .2x.4mm
IIRC
but I will try and measure the contact force , I'm guessing at this stage
of
order 10 gm. Once one wiper lifts I imagine its not long before all 3 lift
at some part of their travel.




Alpha type 4D3-11 pot , footprint 9.6x 11.2mm. 2 wiper arcs about 7 and 9 mm
long. Wiper metal 0.1mm thick x 0.3mm.
Could not measure contact force in-situ. With wiper removed from recess, 10
gm would visibly move one wiper relative to the other. No visible track
scoring under a x30 magnification.
Of course , those old enough, would have come across the effect of hardening
grease in cassette tape mechanisms then VCR. Where an arm pivots on an axle
and return action is just a light torsion spring.