The primary benefit of worm gears is their capability to provide high reduction ratios and correspondingly high torque multiplication. They can even be employed as quickness reducers in low- to medium-quickness applications. And, because their lowering ratio is founded on the quantity of gear teeth alone, they are smaller sized than other styles of gears. Like fine-pitch business lead screws, worm gears are usually self-locking, making them suitable for hoisting and lifting applications.
Although the sliding contact decreases efficiency, it provides extremely quiet operation. (The usage of dissimilar metals for the worm and equipment also contributes to quiet operation.) This makes worm gears suited to use where sound should be minimized, such as for example in elevators. In addition, the utilization of a softer materials for the apparatus means that it can absorb shock loads, like those skilled in serious equipment or crushing equipment.
The meshing of the worm and the gear is an assortment of sliding and rolling actions, but sliding contact dominates at high reduction ratios. This sliding action causes friction and temperature, which limits the effectiveness of worm gears to 30 to 50 percent. So as to minimize friction (and for that 
reason, high temperature), the worm and equipment are constructed with dissimilar metals – for instance, the worm could be made of hardened steel and the gear manufactured from bronze or aluminum.
Such as a ball screw, the worm in a worm gear may have a single start or multiple starts – meaning that there are multiple threads, or helicies, on the worm. For a single-start worm, each full convert (360 degrees) of the worm increases the equipment by one tooth. Thus a gear with 24 teeth will provide a gear reduction of 24:1. For a multi-begin worm, the gear reduction equals the number of teeth on the gear, divided by the number of starts on the worm. (This is different from almost every other types of gears, where in fact the gear reduction is usually a function of the diameters of the two components.)
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