The manufacturing ways of worms are roughly divided among cutting, heat treated and ground after cutting and rolling. And for worm wheels, they could be roughly divided among cutting the teeth, cutting teeth after casting, and teeth cutting after the outdoors rim is usually cast around the guts of the blank.
As for the resources for worm gears, for worms: structural carbon metal (S45C, etc.), structural alloy steel (SCM415, etc.), stainless steel and cast iron happen to be employed; and for worm tires: cast iron (FC200, etc.), nonferrous metals such as for plastic worm gear example phosphor bronze and specialty bronze (nickel bronze, aluminium bronze, etc.), engineering plastics such as for example MC Nylon, etc. As the combination of products for worms and worm tires influences the allowable transmission pressure and lubrication strategies, the decision of mating resources requires careful consideration. Also, related to the friction of the teeth, a harder materials for worm than worm wheel is generally used.
Ordinarily the business lead angles of the right and kept tooth surface of a worm will be the same. However in duplex worm gears, they are created so that the tooth thickness of the worm changes continuously in the axial way so that by shifting the worm axially with shims, it becomes possible to adjust the backlash.
If a worm gear is used, a big speed reduction can be obtained in a compact space in comparison to using spur gears. Generally, the worm can be used to carefully turn the worm steering wheel. However when the lead angle is especially small, the worm steering wheel cannot turn the worm in fact it is named its self locking characteristic. This works extremely well effectively in a few applications but it can not be 
called ideal preventative for invert driving. (When the lead angle is usually large, you’ll be able to turn the worm with the worm wheel.) Furthermore, there are many advantages to worm gears such as for example low sound and vibration, but due to the significant sliding at the tooth areas (sliding contact), the productivity can be low. (For cylindrical worm gears, the overall efficiency is approximately 30-90%.) Also, there are cons such as they tend to suffer from tooth surface heating seizure.