The advisable components for the worm are hardened steel and bronze for the worm gear. However, depending on the software, unhardened metal worms can operate sufficiently and far more economically on forged iron worm gears rated at 50%. In addition to metal and hardened steel, worms are obtainable in stainless steel, aluminum, bronze, and nylon worm gears are available in metal, hardened steel, stainless metal, aluminum, nylon, and non-metallic (phenolic).