Worm gears are usually used when large rate reductions are needed. The reduction ratio is determined by the number of starts of the worm and quantity of tooth on the worm equipment. But worm gears possess sliding contact which is silent but tends to produce heat and also have relatively low transmission effectiveness.
For the materials for creation, in general, worm is made from hard metal as the worm gear is manufactured out of relatively soft steel such as aluminum bronze. That is because the number of teeth on the worm equipment is relatively high in comparison to worm with its number of begins being usually 1 to 4, by reducing the worm equipment hardness, the friction on the worm teeth is reduced. worm wheel china Another characteristic of worm manufacturing may be the need of specialized machine for gear slicing and tooth grinding of worms. The worm equipment, however, may be made out of the hobbing machine used for spur gears. But due to 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 equipment boxes, fishing pole reels, guitar string tuning pegs, and where a delicate acceleration adjustment by utilizing a huge speed reduction is needed. While you can rotate the worm equipment by worm, it is normally not possible to rotate worm by using the worm gear. This is called 
the personal locking feature. The self locking feature cannot continually be assured and another method is preferred for accurate positive reverse prevention.
