[Boatanchors] Milliammeter shunt resistance wire > sources?

[Drew P.]

On making shunts for milliammeters, Roger wrote

"You might try a length of light bulb filament wire. You are not heating it to light hot so it will last as a resistor in free air."

I unsuccessfully tried soldering to a piece of tungsten (light bulb filament wire) back in my much younger years and haven't tried since. A problem with tungsten as a shunt is that heating caused by current flow causes large (as compared to copper or nichrome) resistance changes.  Your meter scale would need to be compressed at one end.

Fine enamelled copper wire wound on the body of a resistor works reasonably well as a shunt in this application.  The resistor is being used as a form only and the resistance of the shunt will be low in any case so a resistor of, say, 100 ohms or higher would be suitable. I did this many years ago using a 2 watt resistor and wire from a deflection yoke, both salvaged from the same junk TV set (definitely the right price).

Another approach is to use a standard resistor value as the current sampling (shunt) resistor.  The value is chosen to be somewhat higher than actually required (the required value is likely not standard). The resultant excessive sensitivity is then adjusted downward by use of another resistor in series with the milliammeter.
  
Yet another scheme is to use a parallel combination of standard values as a shunt resistor.

Drew