“The most important workcomes in the beginning,” Sachs says. Before he picks up thetorch, he picks up the phone to interview the client about his riding style, his other bikes and the intended use for the frame. Combining that info with the rider’s body measurements, Sachs decides on the frame’s proportions and materials, aiming for a precisely tailored fit. When the tubes have been measured and hand-mitered so that each end fits perfectly against the adjacent one, Sachsdry fits the pieces in a jig to make sure that he’s not building tension into the frame. “You have to make sure the tubes aren’t fighting each other,” he says. “Steel has a memory, and even if it looks straight, it can have inherent stresses that work themselves into the bike down the road.” When he’s satisfied with the tolerances throughout,he pins each joint with ordinary finishing nails.  Crafted With Fire: Cleanliness is critical if you want 56 percent silver brazing material to flow easily around steel lugs and tubes. Sachs removes traces ofoil from the joint with an 80-grit aluminum oxidecloth, first stropping the tube—“It gives it tooth”—then finishing by sanding. “I work everything in the direction I want the capillary action to flow.”Then, he slathers the joint with Type U silver brazing flux and removes the frame from the jig before doing the brazing. He heats each joint toaround 800 F using anacetylene torch that itselfhits 6000 F, keeping his eye not on the regulator setting but on the color and the behavior of the materials. “When you heat metal it’s like a plant growing toward the sun,” Sachs says. “You just need toknow which way it’s going to move.” The heat pulls the silver under the lug, around the nail that’s pinning the joint and out theother side of the joint. Finished Lightly: The end result of painstaking effort—and a34-year learning curve:a perfect joint. Sachs’s final, somewhat stern note: While it’s easy to clean up messy brazing after the fact, a quality joint requires little finishing work. “You have to be good with the torch,” he says. “Not the file.”