distance between two parallel planes which are tangential to the opposite tooth flanks, and the number of teeth over which the measurement is to be made for a particular gear is based on its total number of teeth and pressure angle, kaugus kahe paralleelse tasapinna vahel, mis on puutujalised vastassuunaliste hambakülgedega, kusjuures hammaste arv, mille üle konkreetse mõõtevahendi puhul mõõta tuleb, põhineb selle hammasratta hammaste koguarvul ja hambumisnurgal