Worm Gears

Carnes-Miller Gear can manufacture complete, or cut teeth and grind as a service both worm and worm gears.

Another term for worm gear is worm wheel. It has external teeth much like a spur gear but has a throated diameter as well. CMG has the capacity for a maximum diameter worm gear of up to 16in/400mm in diameter. CMG uses the hobbing process to cut the teeth in a worm wheel. Common materials for Worm Wheels include:

  • CDA 954 Aluminum Bronze
  • CDA 932 Bronze
  • Other materials such as steel are also suitable

Worm and Worm Shafts

The worm is the mating threaded profile for the worm wheel. Our capacity is limited to a maximum diameter 4in/100mm and a maximum length of 6in/150mm and up to six starts. Since worms are normally made from a carburizing grade of steel, it is usually rough machined, carburized and hardened, and lastly the threads are finish ground. We can manufacture from 1 up to 6 single or multiple start worms with a right- or left-hand lead.

If a used or sample worm and worm gear can be provided, Carnes-Miller Gear can reverse engineer and duplicate the set. Because the tooth geometry for the worm gear comes from the worm, the worm gear by itself is not enough. We are able to validate our calculations on our WGT500 Gear Analyzer to the sample provided.

CMG has many worm hobs available in both metric and english units in its tool crib. The result is This often allows us to avoid tool up-charges and enables quick turn around. In the case that the hob is special, we can sometimes calculate a solution utilizing a standard worm hob. Worm and worm gears do require a method to check the proper backlash at the proper center distance. A worm tester that rolls the worm gear with the worm is the preferred method but for small volume replacements there are other alternatives.