Two important principles in gearing are pitch surface and pitch position. The pitch surface area of a gear is the imaginary toothless surface area that you would have by averaging out the peaks and valleys of the average person teeth. The pitch surface of an ordinary gear is the form of a cylinder. The pitch angle of a gear is the angle between your face of the pitch surface and the axis.

The most familiar types of bevel gears have pitch angles of significantly less than 90 degrees and therefore are cone-shaped. This kind of bevel gear is called external since the gear teeth stage outward. The pitch areas of meshed external bevel gears are coaxial with the gear shafts; the apexes of the two areas are at the idea of intersection of the shaft axes.

Bevel gears which have pitch angles in excess of ninety degrees have teeth that point inward and are called internal bevel gears.

Bevel gears that have pitch angles of precisely 90 degrees possess teeth that time outward parallel with the axis and resemble the points on a crown. That is why this kind of bevel gear is named a crown gear.

Mitre gears are mating bevel gears with equal numbers of teeth and with axes at right angles.

Skew bevel gears are those for which the beval gear china corresponding crown equipment has the teeth that are directly and oblique.