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 teeth, cutting tooth after casting, and the teeth cutting after the outdoors rim is certainly cast around the center of the blank.
As for the components for worm gears, for worms: structural carbon metal (S45C, etc.), structural alloy steel (SCM415, etc.), stainless steel and cast iron are utilized; and for worm wheels: cast iron (FC200, etc.), non-ferrous metals such as for example phosphor bronze and specialty bronze (nickel bronze, aluminium bronze, etc.), engineering plastics such as MC Nylon, etc. Because the combination of products for worms and worm tires impacts the allowable transmission push and lubrication methods, the choice of mating elements requires consideration. Also, linked to the friction of teeth, a harder material for worm than worm wheel is generally used.
Ordinarily the business lead angles of the right and still left tooth surface of a worm will be the same. 
Yet, in duplex worm gears, they are created so that the tooth thickness of the worm changes consistently in the axial route to ensure that by shifting the worm axially with shims, it turns into possible to adapt the backlash.
If a worm equipment is used, a large speed plastic worm gear lowering can be acquired in a compact space compared to using spur gears. Generally, the worm can be used to turn the worm steering wheel. However when the lead position is particularly small, the worm wheel cannot turn the worm and it is called its self locking feature. This can be used effectively in some applications but it can not be called ideal preventative for invert driving. (When the lead angle can be large, you’ll be able to change the worm with the worm wheel.) In addition, there are many benefits to worm gears such as low noises and vibration, but due to the huge sliding at the tooth surfaces (sliding contact), the effectiveness is certainly low. (For cylindrical worm gears, the overall efficiency is approximately 30-90%.) Also, there are disadvantages such as they tend to suffer from tooth surface warmth seizure.
