How a bolt is made without cutting away a single chip of metal. Most structural bolts are cold formed, also called cold headed. Steel wire is shaped at room temperature by forcing it into hardened dies under enormous pressure. Instead of machining material away, the metal is moved plastically into its final shape. The process: - Wire rod is drawn through a die to a precise diameter, often after spheroidize annealing to soften the steel and improve formability - A cutoff station shears a slug to exact length, since volume is conserved and must match the finished part - Multi-station headers, often 3 to 6 stations, progressively upset the slug, gathering material into the head in stages to avoid buckling - A trimming die shears the hex profile, or the hex is formed directly in the die - Threads are rolled, not cut: hardened dies displace material radially to form the thread profile - Higher grades like 8.8, 10.9, and 12.9 are quenched and tempered to reach target strength Why cold for...