Winding springs

[Mr Ron]

I have watched some videos on making springs and read about it in text books, so I know the principals of spring winding on a lathe. One way of doing it was to wind around an arbor with the coils tight against each wind; then stretching past it's elastic limit to produce a compression spring. Another way was to wind using a thread pitch to produce a compression spring directly. I was wondering if I could wind the wire around a threaded rod or screw letting the wire follow the thread pitch. I don't know if this is an acceptable way to do it.

[Harold_V]

It's been many years since I last wound a spring, but I think it's safe to say that using a threaded form would work well enough, assuming you duplicate the pitch when winding the desired spring. That would be important if the overall length is quite long. For just a few turns, maybe not so important, depending on the distance between the created spring and the restraint used on the wire.

When you unleash the restraint on the created spring, do remember that it will change the size, due to spring back. Pitch, too, is likely to change.

I'd enjoy seeing what you manage to create if you make the attempt.

H

[jcfx]

The only problem I see in using a threaded rod is that you wont be able to make
the tight coiled lead in and out of the spring, it would depend on the wire gauge that
you're using whether you need that lead in and out, grinding the ends flat would work on thicker gauge wire.

I prefer using the thread pitches on the norton box on my lathe to make compression springs with
mandrels of various sizes, metric and inch because of what Harold said about spring back.

[Mr Ron]

I didn't take the tight coils at the beginning and end of the spring into account; good point. I guess I'll go back to the approved way of winding a spring.

[Mr Ron]

I tried winding a spring using .020 piano wire around a 1/4" mandrel (Sexist term in Ca.). After unwinding, the coil was 1/2" diameter. I wanted 3/8" diameter and a bit stiffer spring. I'm guessing .030 wire would be better, but I don't know what diameter of mandrel to use. The free coil length will be about 5/8", compressed to about 1/4".

[mklotz]

I tried winding a spring using .020 piano wire around a 1/4" mandrel (Sexist term in Ca.). After unwinding, the coil was 1/2" diameter. I wanted 3/8" diameter and a bit stiffer spring. I'm guessing .030 wire would be better, but I don't know what diameter of mandrel to use. The free coil length will be about 5/8", compressed to about 1/4".

I wrote a program to calculate the proper mandrel size for spring winding. It's based on Kozo Hiraoka's article in "Home Shop Machinist", July/August 1987, pg. 30.

You can download it from my page. Look for the MANDREL archive.

[Magicniner]

Older versions of Machinery's Handbook have a table for mandrel size & wire size for finished spring size for Piano Wire.
Hemingway Tools have a kit for a spring winder which is adjustable for pitch (http://www.hemingwaykits.com/cgi-bin/sh ... aHK_201970) but it's easy to make something to do the job once you grasp the concept.

[Mr Ron]

I wound a spring using .030 MIG wire around a 1/4" mandrel and it came out perfect. It turned out slightly less than the 3/8" diameter spring I was wanting. With a little tweaking of the mandrel diameter I will get to 3/8". I made it as a tension spring and stretched it out into a compression spring form.