Cutting Methods

Not all broach teeth are designed to cut the same way. The choice of cutting method affects accuracy, surface finish, tool life, and the types of workpieces that can be handled successfully.

Radial (or upward) cutting is the most common approach. Each tooth's groove in the workpiece serves as a guide for the next tooth, which is positioned slightly outward or upward. This method yields excellent profile accuracy and has the added benefit that tooth dimensions do not change after resharpening. However, because the side rake angles tend to be small, chips can adhere to the blade more easily.

Double-cut (roughing then finishing) methods separate the process into two distinct stages. Roughing teeth remove the bulk of the material, and a separate set of finishing teeth handles final sizing. Because the finishing teeth take only a light cut, cutting forces during the final stage are low. This reduces workpiece distortion and produces more consistent dimensions across a batch, making it the preferred method for thin-walled parts, fir tree profiles, and any application demanding tight tolerances.

Back taper relief is a specialized approach where the tooth thickness decreases slightly from front to rear, and side relief is applied to each blade. This is particularly effective for materials prone to adhesion on the cutting edges, such as aluminum, or for workpieces with long cut lengths where chip evacuation becomes challenging.

Progressive form cutting uses roughing teeth that incrementally build up the profile shape, followed by finishing teeth ground to the exact final geometry of the workpiece. This method is especially well-suited for gear broaches and high-precision spline applications where the finished tooth profile must meet demanding accuracy requirements.