[GreenKeys] [External] Yet another part needed for my 15

[Jones, Douglas W]

From: steve bennett via GreenKeys [greenkeys at mailman.qth.net]

> I'll need some springs to return the type bars.

I've made (and modified) many coil springs over the years.  What you need the right diameter of spring wire.  You can get guitar strings at music stores. and yard-long chunks of piano wire at the specialty metal bins in craft stores and hardware stores.  Get wire as close to the wire size of the spring you want to replace, find a chunk of wire or tubing a bit smaller than the hole down the length of the spring you're trying to duplicate, then clamp both together and start winding.  A late or electric drill can provide automation, and it's handy to use a heavy denim rag to protect your thumb.

There are youTube videos on the subject.

The coil form needs to be smaller than the coil diameter you want because it'll spring back a bit when you release the tension you applied during winding.

Cut the spring to length, bend the final turn(s) out to make loops for hooking the spring in place, and then measure the tension you get against a reference spring of the right kind.  If it is too soft (not enough tension), stretch the spring a bit, cut off the excess, and re-measure.  If it is too tight, you'll have to start over with a smaller diameter spring wire or a larger diameter core (either one will make a spring that takes less force to stretch.)

         Doug Jones
         jones at cs.uiowa.edu