@ Lew
Yes, that makes perfect sense, or at least lines up with my world view. The reason for using that site was that plugging in the numbers is likely to get me to a closer result more quickly, but from the look of it its just not that useable. I really wanted a program where I could enter the wire type/diameter, spring diameter, number of turns, length etc which would then tell me the spring constant (in a form I could understand).
Thanks for the swift reply
picclock