The steel is used for high strength worm gears (worm wheel) and steel may be plain carbon steel or alloy steel. The metal gears usually are heat treated as a way to combine effectively the toughness and tooth hardness.
The phosphor bronze is trusted for worms drive as a 
way to reduce wear of the worms which will be excessive with cast iron or steel.
Worm gear sets are usually used to lessen speed and maximize torque. Since the worm drive undergoes more contact anxiety cycles than the worm gear, the worm travel is normally of a better material.
• Cast iron provides strength and ease of manufacture.
• Cast steel provides less difficult fabrication, strong functioning loads and vibration level of resistance.
• Carbon steels are economical and good, but are susceptible to corrosion.
• Aluminum can be used when low gear inertia with some resiliency is required.
• Brass is inexpensive, simple to mold and corrosion resilient.
• Copper is easily formed, conductive and corrosion resistant. The gear’s strength would boost if bronzed.
• Plastic is inexpensive, corrosion resistant, silent operationally and can overcome missing pearly whites or misalignment. Plastic is significantly less robust than steel and is susceptible to temperature changes and chemical corrosion. Acetal, delrin, nylon, and polycarbonate plastics are common.
This 27 tooth brass worm gear will be used in combination with a worm gear to make a 27:1 reduction in speed while also changing the orientation of the rotating axis by 90 degrees. This gear fastens to a 1/4″ shaft by using a particular 1/4″ D-hub to be utilized with 1/4″ D-shaft.
The manufacturing ways of worms are roughly divided among cutting, heat treated and ground after cutting and rolling. And for worm wheels, they may be approximately divided among cutting the teeth, cutting the teeth after casting, and pearly whites cutting after the outdoors rim is definitely cast around the guts of the blank.