The steel is utilized for high strength worm gears (worm wheel) and steel could be plain carbon steel or alloy steel. The steel gears are often heat treated so that you can combine effectively the toughness and tooth hardness.
The phosphor bronze is trusted for worms drive to be able 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 travel undergoes more contact stress cycles compared to the worm gear, the worm travel is usually of a more powerful material.
• Cast iron provides sturdiness and ease of manufacture.
• Cast steel provides much easier fabrication, strong working loads and vibration level of resistance.
• Carbon steels are inexpensive and solid, but are susceptible to corrosion.
• Aluminum can be used when low gear inertia with some resiliency is required.
• Brass is inexpensive, easy 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, noiseless operationally and can overcome missing tooth or misalignment. Plastic-type material is much less 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 with a worm gear to produce a 27:1 decrease 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 specific 1/4″ D-hub to be used 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 are often approximately divided among cutting tooth, cutting pearly whites after casting, and tooth cutting after the outdoors rim is certainly cast around the center of the blank.