I have seen a compression coil spring with a tightly wound central part. Does such a spring (unequal pitch) have a smaller spring constant? Will it grow later? If the center is in close contact and there are two springs at both ends, I feel that the spring constant increases. If we consider the center as an inactive part and simply subtract it from the total number of turns, I feel that the spring constant will be smaller. In my opinion, I think the first possibility is more likely to happen.
Thank you for writing to us, Kashimashi! In this case, the spring constant is stronger than when coils all are evenly spaced (equal pitch).
* As the number of active turns decreases, the spring constant increases.
