Noteheads may be black (a circular or oval shape filled in) or white and are used on the staff to indicate pitch. The shape of noteheads has differed historically, as in plainchant.

Analysis shows that the distribution of meshing points is a function of the axial circular pitch, the axial space of two meshing points on a tooth and the effective width of the gear.

Special worm gear hobs with circular tooth, double pitch and involute etc, can also be ordered.