Screws are primarily manufactured using screw machines that automate the machining and threading process from round stock, allowing for high-speed production. Small gears can be produced by stamping steel sheets, similar to cookie cutters, rather than casting, which often requires additional machining. Stamping does not necessitate heating the metal to red hot; cold punching can effectively shape thick mild steel without compromising the integrity of the final product. Concerns about machining tiny components, such as those found in wristwatches, are addressed by specialized machine tools designed for precision work. Overall, both screws and gears can be efficiently manufactured using distinct yet effective methods tailored to their size and application.