14½° has been used in the past but is no longer recommended by the standard. Preferred pressure angles (according to ANSI B6.1) are 20° and 25°, although they do recognise other angles for specialist applications. Whilst you’re not limited to the ANSI standard’s recognised values, as intermediate pitches are perfectly acceptable from an operational and performance perspective, you may encounter problems with general interchangeability. However, according to the standard a diametric pitch of 20 may treated as both coarse and fine. The standard's coarsest recognised fine pitch is 24 and their finest is 120. The design standard ‘ANSI B6.1’ provides a list of recognised diametric pitches, the coarsest being ‘π÷10’ and the least coarse being 20. Some typical configurations are shown in Fig 2. Diametric Pitch (Pᵈ)Īll pinions and gear wheels are specified by defining the total number of teeth relative to the pitch diameter of the pinion or gear the larger the number, the smaller the relative tooth height or the finer the pitch specification. If you state the properties of the pinion and the rotational ratio, your gear wheel may be designed fully with no further information, assuming it has the same thickness as the pinion. The gear is the driven (output) wheel and has the same tooth height and pitch as the pinion. See Hobbed Teeth vs Shaved or Ground Teeth below Gear If your pinion has non-standard tooth heights, you will also need to state the factor(s) to be applied to the addendum and/or dedendum.

The following additional information is normally also requiredį) shaft diameter (including key dimensions)

Its specification generally requires the following minimum information ( Fig 1): The pinion is usually (but not necessarily) the basis for sizing the driven gear. The pinion is the driver (or input) gear wheel fitted to the electric or diesel motor output shaft and provides the rotary movement that will be transferred to the driven gear (wheel).

Fillet radisu spur gear