I wonder why the decompressed/free length of a spring doesn't change the spring constant $k$. I'll give the equation for $k$ here:
$k = \frac{Gd^4}{8nD^3}$
For a fixed number of coils, if the free length was longer, wouldn't the resulting spring be stiffer? That is, it becomes closer to a straight rod rather than a coil.
With this online calculator, changing the "free length" affects the value of "Maximum Load Considering Solid Height" (AFAIK, it's the maximum load to compress the spring to its solid height). How does the calculator compute that given that the free height has no affect on $k$?
Any help will be appreciated.
