1 Scope and field of application
This International Standard establishes the conventional representation of the toothed
portion of gears including worm gearing and chain wheels. It is applicable to detail
drawings and assembly drawings.
As a fundamental principle a gear is represented (except in axial section) as a solid
part without teeth, but with the addition of the pitch surface in a thin long chain
line.
NOTE For uniformity all figures in this International Standard are in first angle projection
(Method E). It should be understood that the third angle projection (Method A) could
equally well have been used without prejudice to the principles established.