Worm gears are often used when large rate reductions are needed. The decrease ratio is determined by the number of starts of the worm and quantity of tooth on the worm equipment. But worm gears have sliding get in touch with which is calm but tends to produce heat and also have relatively low transmission efficiency.
As for the materials for creation, in general, worm is made from hard metal as the worm gear is made from relatively soft metal such as for example aluminum bronze. That is because the number of tooth on the worm equipment is relatively high in comparison to worm using its number of starts being usually 1 to 4, by reducing the worm gear hardness, the friction on the worm tooth is 
reduced. Another feature of worm manufacturing is the need of specialized machine for gear trimming and tooth grinding of worms. The worm equipment, on the other hand, may be made with the hobbing machine used for spur gears. But because of the various tooth shape, it is not possible to cut many gears at once by stacking the apparatus blanks as can be carried out with spur gears.
The applications for worm gears include gear boxes, fishing pole reels, guitar string tuning pegs, and in which a delicate velocity adjustment by utilizing a big speed reduction is necessary. When you can worm wheel china rotate the worm gear by worm, it is generally not possible to rotate worm by using the worm gear. That is called the personal locking feature. The self locking feature cannot continually be assured and another method is preferred for true positive reverse prevention.