Let's use T, for example, T30*6, where 30 is the outside diameter and 6 is the tooth pitch. The Angle of trapezoidal teeth is 30°, and the Angle of imperial teeth is 29°. The tooth shape is like an isosceles trapezoid, narrow at the top and wide at the bottom. The trapezoidal teeth are relatively simple to process, and the tightness of the nut and screw can be adjusted according to the depth of the teeth.