David Bayer wrote:

> Wait a minute, are you inserting donuts in the spring coils or between the
> perch and the top of the spring? Inserting the doughnut between coils would
> reduce the number of active coils, but inserting it between the spring perch
> and the top of the spring would not as you are not changing the spring at all
>
> dave

 A spacer effectively reduces coils as follows.  Take a spring ten inches long
that has 10 coils.  Put a spacer 2 inches wide on top.  Now, fit the spring in
between fully extended spring perches that are 10 inches apart.  You have to
compress the spring 2 inches to do this since the spring perches will not expand
any further to accomidate the 2" spacer, and the spacer and spring have a
combined length of 12".  Thus, you compress the spring so it is now 8" long with
a 2" solid spacer on top.  You have thus effectively taken out two colis without
changing spring length, given this hypothetical 10" spring with 10 coils.  Now
this spring...as pre-loaded...is stiffer than a non-pre-loaded spring.  The same
weight will compress it less that the 10" spring without a spacer.