What is the equivalent number of teeth of helical rack?

When milling helical rack, the tool number should be selected according to the equivalent number of teeth. Do you know what is the equivalent number of teeth of helical rack? Let's introduce the gear pinion to you.

According to the geometric relationship, the intersection of the normal plane and the indexing cylinder at a certain point on the tooth line of the helical cylindrical gear is an ellipse. The larger curvature radius of the ellipse is taken as the indexing circle radius of an imaginary spur gear, and the normal modulus and normal profile angle of the helical gear are taken as the modulus and profile angle of the imaginary spur gear. The imaginary spur gear is called the equivalent gear of the helical gear. The so-called equivalent number of teeth of helical cylindrical gear refers to the equivalent number of teeth of the helical cylindrical gear.