The suggested materials for the worm are hardened metal and bronze for the worm gear. Even so, dependent on the software, unhardened steel worms can operate adequately and a lot more economically on forged iron worm gears rated at 50%. In addition to steel and hardened metal, worms are obtainable in stainless steel, aluminum, bronze, and nylon worm gears are offered in steel, hardened steel, stainless steel, aluminum, nylon, and non-metallic (phenolic).