Worm Gears are correct angle drives providing huge swiftness ratios on comparatively brief center distances from 1/4” to 11”. When correctly mounted and lubricated they function as quietist and smoothest running type of gearing. Because of the high ratios feasible with worm gearing, optimum speed reduction can be accomplished in much less space than a great many other types of gearing.
EFFICIENCY of worm gear drives depends to a large level on the helix position of the worm. Multiple thread worms and gears with higher helix position prove 25% to 50% better than single thread worms. The mesh or engagement of worms with worm gears produces a sliding Nylon Gear Rack action leading to considerable friction and greater loss of efficiency beyond other types of gearing. The utilization of hardened and surface worm swith bronze worm gears increases efficiency.
LUBRICATION can be an essential factor to boost performance in worm gearing. Worm gear action generates considerable heat, decreasing efficiency. The amount of power transmitted at a given temperature raises as the effectiveness of the gearing raises. Proper lubrication enhances effectiveness by reducing friction and high temperature.
RATIOS of worm equipment sets are determined by dividing the number of teeth in the apparatus by the number of threads. Thus one threads yield higher ratios than multiple threads.
SAFETY PROVISION: Worm gearing shouldn’t be used as a locking mechanism to hold weighty weights where reversing actions could cause harm or injury. In applications where potential harm is non-existent and self-locking is desired against backward rotation then use of an individual thread worm with a minimal helix angle immediately locks the worm equipment drive against backward rotation.
MATERIAL recommended for worms can be hardened steel and bronze for worm gears. However, depending 
on the application unhardened steel worms operate adequately and more economically with cast iron worm gears at 50% horsepower ratings. In addition to steel and hardenedsteel, worms are available in stainless, aluminium, bronze and nylon; worm gears are available in steel, hardened steel, stainless, aluminum, nylon and non-metallic (phenolic).
Gear racks are utilized to convert rotating movement into linear motion. A equipment rack has straight teeth cut into one surface of a sq . or round portion of rod and operates with a pinion, which is usually a small cylindrical equipment meshing with the apparatus rack. Generally, gear rack and pinion are collectively known as “rack and pinion”. There are many methods to use gears.
There are applications where the gear rack is stationary, as the pinion traverses and others where the pinion rotates on a fixed axis as the gear rack moves. The previous is used widely in conveying systems as the latter can be utilized in extrusion systems and lifting/lowering applications.