...Just what constitutes a recoil spring?s weight? The amount of energy stored by a conventionally-wound spring as it is compressed changes value in a straight line. For example, if you compress a conventional spring an inch, it may store a pound of energy. Compressing it another inch will store an additional pound of energy. At three inches we would have 3 pounds of energy stored.
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I'm surprised at that terminology from Wolff. If you compress a spring with a
rate of 1.0 lbs/inch it will give you one pound of
force not energy. Three inches compression = 3 lbs of force. You can think of it like a weight. Energy storage is not the same thing.
If one had a precise fixture to compress the spring to that length, a force gauge would provide a direct reading of the spring force. Measurement fixtures and methods, however, will have a significant effect on the readings.