THE MAN BEHIND THE HAMMER
Metalworking for the common man, or destruction as learning process
By Mark Hoyer
Wilcox grew up immersed in Southern California motor culture. The first real motorcycle young Evan ever saw was an AJS 500 down the block. He recalls: “The big Single never ran, but it was the most impressive memory of beauty and design of my youth. It had an aluminum gas tank, and I studied it often.”
In high school, Evan "made a beeline for metal shop." His directness had a purpose. After seeing On Any Sunday, Wilcox and his friends stripped down their trailbikes, hand-making expansion chambers, seats, footpegs and so on. He began imitating the spare, functional look of racing bikes he had seen at Ascot Park half-mile and TT events.
In shop classes, building expansion chambers, Evan found a practical use for high school math. “My geometry teacher taught me how to lay out a cone so the ends would be flat when rolled. The heavens opened and the angels sang! I was on my way.”
Wilcox confesses that he never saw anyone shape aluminum before he started himself, repairing old BSA and AJS tanks for vintage bike friends. Eventually, someone recommended a book, Ron Fournier's Sheet Metal Handbook. From this essential manual, Wilcox really learned his art.
Shaping compound curves from sheet aluminum requires patience, skill and experience. In a high-tech world, aluminum-shaping tools seem almost medieval. Metal formers work with many kinds of wooden and plastic mallets, sandbags, cutters, dollies, slappers, whappers–even sawed-off tree trunks!
There’s also the English Wheel, introduced in larger numbers to the United States during the 1980s. This device presses and smooths out the hand-hammered dents in the aluminum. The formed (but dented) aluminum is run by hand between two precision rollers or “wheels.” Typically, the larger, upper wheel is about 8 inches in diameter with a flat working face. The smaller, lower wheel has a working surface that can range from flat to semicircular. Normally, an English Wheel has a set of interchangeable lower wheels that have faces with different radii. Metal shapers pick particular rollers, or a sequence of rollers, to smooth out hammer marks and add larger curves.
Characteristically, Wilcox bought a set of plans, built his own English Wheel, and then taught himself how to use it.
Gas welding aluminum is an equally devilish art to master, and a necessary one. Aluminum gas tanks are welded together in sections. Wilcox gas welds with pure aluminum rod because this operation doesn’t leave the area around the weld embrittled and susceptible to vibration-cracking. With exactly the right amount of heat and rod, you get a beautiful bead. But with just a bit too much heat, you open an ugly hole.
In the beginning, Evan says, “My reality was blown holes or corners falling off entirely. I learned that it’s all about being sensitive to the required temperature window (1100 to 1200 degrees) and adjusting to thicker or thinner sections.
“This,” he explains, “is a dance where the metal leads.”
Photo by: David Perry