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