Chordal height

The chordal tooth thickness s_n is the shortest distance between the tooth traces at a distance ha from the tooth tip. The chordal tooth thickness s_n, measured across the height h_a, applies to the finished gear (actual test dimension).

The specified chordal tooth thickness and the corresponding height are also used to determine the section of the involute in which the flank area lies. Therefore, these values can be given as an alternative to the addendum modification coefficient or other test dimensions.