Why Not to Use Worm Gears
There is one particularly glaring reason why one would not choose a worm gear more than a standard gear: lubrication. The movement between the worm and the wheel equipment faces is completely sliding. There is no rolling element of the tooth get in touch with or conversation. This makes them fairly difficult to lubricate.
The lubricants required are often very high viscosity (ISO 320 and higher) and thus are tough to filter, and the lubricants required are usually specialized in what they do, requiring a product to be on-site particularly for that kind of equipment.
Worm Gear Lubrication
The primary problem with a worm gear is how it transfers power. It really is a boon and a curse at the same time. The spiral motion allows large sums of decrease in a comparatively little bit of space for what’s required if a typical helical equipment were used.
This spiral motion also causes an incredibly problematic condition to be the primary mode of power transfer. That is commonly known as sliding friction or sliding put on.
With a typical gear set the energy is transferred at the peak load stage on the tooth (referred to as the apex or pitchline), at least in a rolling wear condition. Sliding happens on either side of the apex, but the velocity is relatively low.
With a worm gear, sliding motion may be the only transfer of power. As the worm slides over the tooth of the wheel, it gradually rubs off the lubricant film, until there is no lubricant film remaining, and for that reason, the worm rubs at the steel of the wheel in a boundary lubrication regime. When the worm surface area leaves the wheel surface area, it accumulates more lubricant, and starts the process over again on another revolution.
The rolling friction on a typical gear tooth requires little in the form of lubricant film to fill in the spaces and separate both components. Because sliding occurs on either part of the gear tooth apex, a somewhat higher viscosity of lubricant than is certainly strictly necessary for rolling wear is required to overcome that load. The sliding takes place at a relatively low velocity.
The worm on a worm set gear turns, even though turning, it crushes against the load that is imposed on the wheel. The only way to prevent the worm from touching the wheel can be to get a film thickness large enough to not have the entire tooth surface area wiped off before that area of the worm is out of the load zone.
This scenario takes a special sort of lubricant. Not only will it should be a relatively high viscosity lubricant (and the bigger the strain or temperature, the bigger the viscosity should be), it will need to have some way to greatly help get over the sliding condition present.
Read The Right Method to Lubricate Worm Gears to learn more on this topic.
Custom Worm Gears
Worm Gears are correct angle drives providing huge speed ratios on comparatively brief center distances from 1/4” to 11”. When correctly installed and lubricated they function as the quietist and smoothest working type of gearing. Because of the high ratios possible with worm gearing, optimum speed reduction could be accomplished in less space than a great many other types of gearing. Worm and worm gears are powered by non-intersecting shafts at 90° angles.
EFFICIENCY of worm gear drives depends to a sizable level 
on the helix position of the worm. Multiple thread worms and gears with higher helix position prove 25% to 50% more worm drive shaft efficient than single thread worms. The mesh or engagement of worms with worm gears generates a sliding action causing considerable friction and higher loss of efficiency beyond other styles of gearing. The usage of hardened and ground worm swith bronze worm gears improves efficiency.
LUBRICATION can be an essential factor to boost efficiency in worm gearing. Worm gear action generates considerable warmth, decreasing efficiency. The amount of power transmitted at a given temperature raises as the effectiveness of the gearing boosts. Proper lubrication enhances performance by reducing friction and high temperature.
RATIOS of worm gear sets are determined by dividing the amount of teeth in the gear by the amount of threads. Thus single threads yield higher ratios than multiple threads. All Ever-Power. worm gear models are available with either left or right hands threads. Ever-Power. worm equipment sets can be found with Single, Double, Triple and Qua-druple Threads.
SAFETY PROVISION: Worm gearing should not be used as a locking mechanism to hold large weights where reversing actions could cause harm or damage. In applications where potential harm is nonexistent and self-locking is desired against backward rotation then use of a single thread worm with a low helix angle instantly locks the worm gear drive against backward rotation.
Materials recommended for worms is usually 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, light weight aluminum, nylon and nonmetallic (phenolic).
Ever-Power also sells gear tooth measuring products called Ever-Power! Gear Gages decrease mistakes, save time and money when identifying and buying gears. These pitch templates are available in nine sets to recognize all the regular pitch sizes: Diametral Pitch “DP”, Circular Pitch “CP”, External Involute Splines, Metric Module “MOD”, Stub Tooth, Fine Pitches, Coarse Pitches and Unusual Pitches. Refer to the section on GEAR GAGES for catalog figures when ordering.