Renold Gears

Renold Gears pioneers the way to replicate thread form for Worms and Worm gears

Worms and worm gears have been manufactured since ancient times. In modern times the profile or tooth form of gearing has been standardised for most types of gears. Helical or spur gear teeth can be defined in terms of pressure angle and NDP (or Module for metric units). Worm gearing has evolved along a different path where pitch, profile or form and proportions of tooth size and height are somewhat arbitrary and determined by the manufacturer and/or the method of manufacture. When equipment is maintained and worm gears are replaced as matched sets then the thread form may not be an issue.  But if owners or users of equipment need only one element or need interchangeable spare parts then there is a need to duplicate the original thread form. The article discusses a method where a sample or artefact can be measured in order to quantify the tooth geometry. The worm, wormwheel or gear set can be duplicated so as to be identical to the original where either or both elements could be used.