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Chapter 4. Maple Mike: > Hey! Let's Build the Trigger! - Pg. 130

Maple Mike Figure 04.26: Today's featured oddball component: The heavily modified RCA jack ferrule. Figure 04.25: Fabricating the trigger rod requires lots of finicky hole drilling and needle file work. It took me three tries to get it should have no trouble getting it right in two. the coily ones we're most familiar with come in two flavours: expansion (pull on it and the spring pulls back, like on your basic articulated desk lamp) and compression (push on it and the spring pushes back, like in a ballpoint pen). You can make your own springs from steel spring wire by winding the wire tightly around a cylindrical form (coils touching for an expansion spring, coils separated for compression), anchoring both ends of the wire, then heating the whole shebang with a torch until the wire just begins to glow. The heating relaxes the tension in the wire to accomodate the cylindrical shape it's been wound around; the tension returns to the wire in its new form when it cools down. [Figure 04.27] Where to get spring wire? Guitar strings are spring wire. Use the plain (unwound) ones for best results, and the heavi- est gauge you can lay your lunch hooks on. How cool is that? It's not quite as easy as it sounds. For one thing, it's an enterprise fraught with peril: until the spring wire has been tensioned properly in its new form, it's essentially a mechani- cal bomb waiting to go off. Lose your grip on either end of the wire and it'll uncoil explosively in a flurry of ninja-like cutting and slashing. Wear eye protection at the very least; work gloves and a leather apron, too, if ya got 'em. For another thing, evenly winding even small-gauge spring wire is no picnic (it's spring wire -- it's springy, dammit), and anchoring the ends is challenging. I've had success using an electric drill as a winder, with hole and slot anchoring. Chuck in brass tubing for the form when winding expansion springs, and coarsely threaded rod for compression springs (the spring wire slots into the thread grooves for nice, even spac- ing of the coils. Clamp the free end of the wire tightly into your bench vise, use the lowest Rs per M you can muster, and keep even tension on the wire as it winds onto the form. Merely bending the wire into the slot at the end of the form isn't gonna work to hold the wound wire solidly in posi- tion. Clamp the spring wire to the form solidly with locking pliers at both ends, release the form from the drill chuck, and fire up the torch for the heat/cool cycle. Once cool, cut the spring wire at the point where it passes through the hole in the form on the (formerly) chuck side of the form; If you did the heat/cool correctly, the spring wire won't uncoil. If you wound an expansion (coils touching) spring on a smooth form, it should slide off the form easily. If you wound onto threaded rod for a compression spring you'll need to carefully cut the form at the base of each side of the slot 119