The recommended resources for the worm are hardened steel and bronze for the worm equipment. However, dependent on the application, unhardened metal worms can operate sufficiently and far more economically on solid iron worm gears rated at 50%. In addition to metal and hardened steel, worms are offered in stainless steel, aluminum, bronze, and nylon worm gears are available in steel, hardened steel, stainless metal, aluminum, nylon, and non-metallic (phenolic).