Active coils?

[clw]

A previous post gave a link to a spring rate calculator. One of the entered measurements is active coils. How do you count and determine what is an active vs. an inactive coil? Can it be a partial count; say 28.7?

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[MACE]

The active coils are the coils which have some space between them and the next coil.

That space gives room for the spring to deform and "act like a spring".

The first coils typically are wound touching to form a "seat" for the spring. Those are not active coils.

I would expect the spring calculator will take fractional values but have not tried it. Just plug in some values and see if the results make sense. The fewer the number of active coils input the stiffer the resulting rate should be.

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MACE

Hey ho, let's go
Hey ho, let's go
Hey ho, let's go
Hey ho, let's go

 

[clw]

Thanks Mace:

I tried a spring of known value (I hope) and was off by 8%. I'll try again tonight. So, does the metal fatigue w/age? Can it sack out or take a set? I thought, probably incorrectly, that springs sacked out with use. Ever seen an old Buick? Or, am I confusing rate with preload? My head hurts!

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