I posted a while back about this P&W comparator I had picked up - a
mechanical device with plus and minus 3 thousandths full scale, and someone
said that the usual failure is the copper spring (a strip of spring copper)
that connects to the pointer - well, they were right, it's broken - is there
an inexpensive source for a replacement? make one? or just use thin
stailess fishing leader?

--
bill
to email me, to to my web page, www.wbnoble.com and find my email
or unscramble the following by removing spaces and correcting the obvious
spelling errors

wil lia m_b_n obl e at msn daught com



--
Posted via a free Usenet account from http://www.teranews.com

"William Noble" wrote in message
.. .
I posted a while back about this P&W comparator I had picked up - a
mechanical device with plus and minus 3 thousandths full scale, and someone
said that the usual failure is the copper spring (a strip of spring copper)
that connects to the pointer - well, they were right, it's broken - is
there an inexpensive source for a replacement? make one? or just use thin
stailess fishing leader?

--
bill
to email me, to to my web page, www.wbnoble.com and find my email
or unscramble the following by removing spaces and correcting the obvious
spelling errors

wil lia m_b_n obl e at msn daught com


--
Posted via a free Usenet account from http://www.teranews.com


You might get a replacement part at a scale place, especially one that does
repair work.

William Noble wrote:
I posted a while back about this P&W comparator I had picked up - a
mechanical device with plus and minus 3 thousandths full scale, and someone
said that the usual failure is the copper spring (a strip of spring copper)
that connects to the pointer - well, they were right, it's broken - is there
an inexpensive source for a replacement? make one? or just use thin
stailess fishing leader?


How tough to get in an out of the unit?

Seems a low cost-risk to try the stainless leader material.

Got a model airplane shop around? They stock music wire in small
sizes, and most, these days, stock a variety of carbon fiber rods and
strips.

A guy could probably scrounge around and find a few strips of Be-Cu
shim that could be used for springs.

Cut with sharp scissors, and don't lick your fingers after. No
polishing, just a really cursory deburr with some sand paper.

Cheers
Trevor Jones

William Noble wrote:
I posted a while back about this P&W comparator I had picked up - a
mechanical device with plus and minus 3 thousandths full scale, and someone
said that the usual failure is the copper spring (a strip of spring copper)
that connects to the pointer - well, they were right, it's broken - is there
an inexpensive source for a replacement? make one? or just use thin
stailess fishing leader?


That was me.

Any metal shim material, non-magnetic. I used to have some copper ones
that I had wire EDM'd back when I used to repair them. Symmetry is
important, as the scale readings will be VERY difficult to calibrate
from plus to minus, if the strip is not symmetrical. Plus or minus .010
or less from center hole to each end hole should be good enough.


--
Steve Walker
(remove wallet to reply)

well, I made the copper spring out of .001 stainless feeler gauge material -
had a little binding, used fishing leader, and after a bunch of messing
around got the comparator basically working, though the leader is a bit too
stiff, I think. Now I've had my fun with this thing, so it's on e-bay here
http://cgi.ebay.com/ws/eBayISAPI.dll...m=300156244915 - I can't
imagine why I would need it, but I hate to turn it into scrap stock for
machining stuff out of. Seems to me the gauge head is probably pretty
obsolete, but the stand is timeless and could be very handy with a modern
gauge head (and the head is held in place with 3 allen head screws, so it's
easy to change).

Anyone else got an idea of what this might be used for (no, an anchor
doesn't qualify, it has to be something in a machine shop - "high precision
reading lamp stand" also doesn't cut it)




"Steve Walker" wrote in message
...
William Noble wrote:
I posted a while back about this P&W comparator I had picked up - a
mechanical device with plus and minus 3 thousandths full scale, and
someone said that the usual failure is the copper spring (a strip of
spring copper) that connects to the pointer - well, they were right, it's
broken - is there an inexpensive source for a replacement? make one? or
just use thin stailess fishing leader?


That was me.

Any metal shim material, non-magnetic. I used to have some copper ones
that I had wire EDM'd back when I used to repair them. Symmetry is
important, as the scale readings will be VERY difficult to calibrate from
plus to minus, if the strip is not symmetrical. Plus or minus .010 or less
from center hole to each end hole should be good enough.


--
Steve Walker
(remove wallet to reply)



--
Posted via a free Usenet account from http://www.teranews.com