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 the teeth, cutting teeth after casting, and the teeth cutting after the outdoors rim is cast around the guts of the blank.
As for the products for worm gears, for worms: structural carbon steel (S45C, etc.), structural alloy metal (SCM415, etc.), stainless and cast iron happen to be used; and for worm wheels: cast iron (FC200, etc.), nonferrous metals such as phosphor bronze and specialized bronze (nickel bronze, metal bronze, etc.), engineering plastics such as for example MC Nylon, etc. Because the combination of materials for worms and worm wheels impacts the allowable transmission force and lubrication methods, the choice of mating elements requires careful consideration. Also, related to the friction of teeth, a harder materials for worm than worm wheel is generally used.
Ordinarily the business lead angles of the proper and left tooth surface of a worm are the same. However in duplex worm gears, they are created to ensure that the tooth thickness of the worm alterations continuously in the axial way to ensure that by shifting the worm axially with shims, it turns into possible to adjust the backlash.
If a worm equipment is used, a huge speed decrease can be obtained in a concise space in comparison to using spur gears. Generally, the worm is utilized to carefully turn the worm steering wheel. However when the lead position is especially small, the worm wheel can not turn the worm and it is named its self locking characteristic. This can be utilised effectively in some applications but it can’t be called best preventative for reverse driving. (When the lead angle is large, you’ll be able to switch the worm with the worm steering wheel.) Furthermore, there are many plastic worm gear advantages to worm gears such as for example low noise and vibration, but due to the significant sliding at the tooth surfaces (sliding contact), the effectiveness is definitely low. (For cylindrical worm gears, the overall efficiency is about 30-90%.) As well, there are cons such as they 
tend to have problems with tooth surface temperature seizure.