The steel can be used for high strength worm gears (worm wheel) and steel could be plain carbon steel or alloy steel. The steel gears are generally heat treated so that you can combine properly the toughness and tooth hardness.
The phosphor bronze is trusted for worms drive so as to reduce wear of the worms which will be excessive with cast iron or steel.
Worm gear units are usually used to reduce speed and boost torque. Since the worm drive undergoes more contact stress cycles compared to the worm gear, the worm travel is generally of a more powerful material.
• Cast iron provides 
sturdiness and ease of manufacture.
• Cast steel provides less complicated fabrication, strong operating loads and vibration level of resistance.
• Carbon steels are economical and solid, but are susceptible to corrosion.
• Aluminum can be used when low equipment inertia with some resiliency is required.
• Brass is inexpensive, simple to mold and corrosion resilient.
• Copper is easily formed, conductive and corrosion tolerant. The gear’s strength would maximize if bronzed.
• Plastic is inexpensive, corrosion resistant, tranquil operationally and can overcome missing tooth or misalignment. Plastic is fewer robust than metal and is vulnerable to temperature alterations and chemical corrosion. Acetal, delrin, nylon, and polycarbonate plastics are common.
This 27 tooth brass worm gear is intended to be used in combination with a worm gear to make a 27:1 decrease in speed while also changing the orientation of the rotating axis by 90 degrees. This equipment fastens to a 1/4″ shaft using a particular 1/4″ D-hub to be used with 1/4″ D-shaft.
The manufacturing methods of worms are roughly divided among cutting, heat treated and ground after cutting and rolling. And for worm wheels, they can be approximately divided among cutting the teeth, cutting teeth after casting, and the teeth cutting after the exterior rim is cast around the guts of the blank.