Spring scale

A spring balance can be calibrated for the accurate measurement of mass in the location in which they are used, but many spring balances are marked right on their face "Not Legal for Trade" or words of similar import due to the approximate nature of the theory used to mark the scale.

A spring balance may be labeled in both units of force (poundals, Newtons) and mass (pounds, kilograms/grams).

Main uses of spring balances are to weigh heavy loads such as trucks, storage silos, and material carried on a conveyor belt.

They are used when the accuracy afforded by other types of scales can be sacrificed for simplicity, cheapness, and robustness.

The first spring balance in Britain was made around 1770 by Richard Salter of Bilston, near Wolverhampton.