Broaching is a machining process that uses a toothed tool called a broach to remove material. Broaches have multiple rows of teeth used to shape the workpiece into the desired form. As the broach is pushed or pulled through the workpiece, each successive tooth chips off a little more material, gradually shaping the workpiece to the required dimensions and finish. Broaching produces precision holes, slots and forms with a smooth surface finish in both ferrous and non-ferrous materials.

Key Types of Broaching Tools

There are several common types of broaching tools designed for different applications:

Rack Broaches

Rack broaches are used to cut internal straight flutes or slots in workpieces. They have teeth arranged in a straight rack pattern. Rack broaches are well-suited for high-volume production of small intricate parts with complex internal forms. They can quickly shape items like gears with many teeth.

Form Broaches

Form broaches contain teeth arranged in curved patterns to cut complex contours like oval, circular or irregular shaped openings. They are used to machine intricate external and internal contour surfaces on components for aerospace, medical and other precision applications. Form broaching provides an economical alternative to machining when complex contours are involved.

Pull Broaches

Pull broaches are designed to cut shoulders, angles, and forms on the outside diameter of parts. They have alternating sets of upper and lower teeth to cut in both directions of their stroke. During Broaching Tools, pull forces are used rather than push forces. Pull broaches work well for cutting forms on small, tightly tolerance workpieces.

Slipline Broaches

Slipline broaches can cut odd-shaped internal forms by using narrow teeth that follow the desired contour. They are efficient for producing unusual shapes that rack, form or pull broaches may not be suited for. Slipline broaching is generally a more expensive process than straight rack broaching but enables complex odd-form production.

Construction of Broaching Tools

Broaching tools are available in solid tool steel as well as brazed-tooth and inserted-tooth configurations. Solid tool steel broaches offer rigidity for heavy-duty applications but are more difficult to produce. Brazed-tooth broaches involve brazing pre-formed tool steel teeth to a shank or holder for easier manufacturing. Inserted-tooth broaches use replaceable carbide or high-speed steel teeth inserted into pockets in the tool body, allowing economical tooth replacement.