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Hand winding torsion springs

By prsxr on: May 10, 2009, 09:06:30 AM

I've had a request to describe how to make some of the springs that I've used in my projects. So I made up a litthow-to as I made up a low-power AR15 hammer spring for my Beretta 38a.

This method will make double-sided torsion springs. I am told that the springs should probably be stress

relieved after bending for maximum fatigue life. I have not done this, assuming my builds will not seethousands of rounds through them. If I have some break, I'd probably just re-make them.

Spring wire is avaiable from McMaster-Carr (along with massive amount of other goodies-- *highly*recommended as a source) as assortments and 100pc quantities of 12" lengths.

The tool shown was made for doing the trigger and sear springs for my PPS FCG I was selling a while ago. Thelong rod is 1/4" diameter, (which determines the diameter of the spring loops) the small part is 3/16" dia

(somewhat smaller than the width of the center part of the spring), with a reduced diameter shank to fit through

the hole in the 1/4" rod. The length of the short piece determines the distance from the loops to the end of thespring. The end of the short piece has a dremeled slot in the end, with one side left long to resist the winding

force, and the other leg shortened to allow the spring to be 'backed out' of the slot when the winding is finished.

The two parts are assembled, and clamped in a vise with sufficient work area below the overhang.

To begin, bend the length of spring wire in the middle with a pair of needle nose pliers to form the center squarebend. Hook the square bend into the slot in the short piece of the tool. While pulling down slightly to keep the

wire seated in the tool notch, bring the loose ends around slowly.

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Try to keep the wires parallel, and tight against the previous loop. As you may see in the picture, I was not

careful while taking pictures, and the far side of the spring has crossover in the loops. It will take practice to dothe forming correctly. Continue coiling the ends until the spring is the way that you want it.

When the spring is complete, it must be removed from the tool. Try to rotate the spring opposite the way youwere coiling, and lift the wire out of the tool slot. This will allow you to remove the short rod of the tool from it

hole, and then slide the completed spring off the end of the tool.

I have found some flexibility is possible in spring dimensions without making a new tool. The slot will

accommodate greater widths of the square bend of the wire, but it does get harder to keep the spring symmetricaIf the coils need to be larger diameter, a bushing can be slipped over the tool. Wrapping with tape sometimesworks with thinner wire.

Hope this technique helps for projects where stock springs just won't do.

As always, questions/comments are appreciated.