worm wheel

Worm gears are usually used when large velocity reductions are needed. The reduction ratio depends upon the number of begins of the worm and number of teeth on the worm equipment. But worm gears have sliding contact which is calm but will 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 steel such as 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 teeth is reduced. Another characteristic of worm manufacturing is the need of specific machine for gear cutting and tooth grinding of worms. The worm equipment, on the other hand, may be made out of the hobbing machine used for spur gears. But because of the different tooth shape, it is not possible to cut a number of gears at once by stacking the apparatus blanks as can be done with spur gears.
The applications for worm gears include gear boxes, fishing pole reels, guitar string tuning pegs, and in which a delicate rate adjustment by utilizing a large speed reduction is needed. When you can rotate the worm gear by worm, it is usually not possible to rotate worm utilizing the worm gear. This is called the personal worm wheel china locking feature. The self locking feature cannot always be assured and a separate method is preferred for true positive reverse prevention.