Help making a circular spring

good luck, Andy

On Mar 21, 4:40 am, George Woodzell wrote:

This would be similar to making a clock spring or a flat mainspring for a gun, you could look at some clockmaking or gunsmithing books for help. Usually the spring steel is supplied annealed in strip or sheet form, it's very soft. Bending it around a mandrel is probably the best way to get a circular form, you'll have to allow for spring-back with the mandrel's diameter, you won't get a perfect one first time out. You could probably use hardwood for onesie-twosie stuff. If you need hooks or loops on the ends, use smooth-jawed chain nose pliers to form same, you DO NOT want nicks on the surface. Polish before hardening. Hardening and tempering will be the challenge. I've had good luck with flat stock springs by coating them with anti-scale compound, then heating them up on a steel plate with a torch until non- magnetic. Heat the underside of the plate, rather than the work directly, cuts down on oxidation. I've used water and I've used oil for quench, on thin work it doesn't seem to make much difference. Carefully polish afterwards, inspect for cracks, it'll be brittle as very thin glass. At this point there's a number of ways to temper. Best is a temperature controlled heat treat oven. Next best is a lead pot with a thermometer, you can get nitre bluing salts from the likes of Brownell's and do the same thing without the lead. Or you can do the expert clockmaker thing with the plate and a torch and eyeball the colors as you heat the plate with the spring on top. Worst would be trying to temper the thing with a bare torch, low success rate there. I use the lead pot with the thermometer, I cast bullets anyway and mine holds temperature within 10-15 degrees, just have to watch the thermometer for when to dunk the spring. You'll probably have to make a number of springs before you get one that's satisfactory, varying temper temperature as one either breaks or sets when testing.

Stan