The spring that John Grant needs looks pretty easy to make by hand.
It takes a little experimentation to determine the right size mandrel
that will produce the desired spring diameter with hand winding
techniques. The mandrel needs to be a little undersized and you need
to be careful to wind with even tension. I would think that maybe the
forth or fifth try would result in a good enough spring.

That said, wire forms such as complex springs are made today by very
clever CNC machines that are fairly easy to program. So I would guess
that it would not be very expensive to have them made if you can find
a company that specializes in small runs.

Spencer Chase
Garberville, California