A comprehensive look at latest standards development efforts.

We know that for cylindrical gears we have the standard DIN 3964 for defining deviations of shaft center distance and shaft position tolerances of casings. And for bevel gears? Is there some specific standard for defining deviations of center distance and shaft position tolerances of casings (orthogonal shafts), as DIN 3964 do?

During the revision of ISO 1328-1:2013 Cylindrical gears — ISO system of flank tolerance classification, ISO Technical Committee TC 60 WG2 delegates discussed proposals that the standard should be modified to ensure that it is compatible with the ISO Geometrical Product Specification (GPS) series of standards (Refs. 1-3). This seems sensible because the gears are geometrical components, but after reviewing the implications, it was rejected because ISO TC 60 WG2 did not think the gear manufacturing industry was ready for such a radical change in measurement strategy. The feasibility of the implementation of gears into the GPS matrix of standards has been carried out and the results conclude that this is practical, provided some key issues related to measurement uncertainty and establishing appropriate KPIs are addressed.

PTB's two microgear measurement standards and their analyses using seven measurement methods which are then presented, evaluated and compared with each other.

If you were offered an opportunity to spend quality time with leading experts in your field, where in-depth discussions and dialogues occurred on subjects that directly impacted your business, would you do it?

A reader asks: I'd like to know about the different approaches and factors considered while determining the value of Ka in regards to the DIN 3990 and AGMA standards.

Germany adopts ISO 1328 standard for the measurement of gears, plus other news and announcements from around the industry.

Although gear geometry and the design of asymmetric tooth gears are well known and published, they are not covered by modern national or international gear design and rating standards. This limits their broad implementation for various gear applications, despite substantial performance advantages in comparison to symmetric tooth gears for mostly unidirectional drives. In some industries — like aerospace, that are accustomed to using gears with non-standard tooth shapes — the rating of these gears is established by comprehensive testing. However, such testing programs are not affordable for many other gear drive applications that could also benefit from asymmetric tooth gears.

A reader wonders about gears where the tops of the teeth are the bearing surface, as used in spur gear differentials. Do they require any special construction or processing?

How difficult is it to design a gear? It depends upon whom you ask.