The broach tool is the vital part of any broaching operation. The tool must be made to the precise size of the final cut desired. With rare exceptions, it cannot be coerced or manipulated to cut a size or dimension that it wasn’t designed for.
Broaching machines can be classified in several basic ways. First, broaching tools can be designed to cut internal or external surfaces. In the case of internal broaching, there must be a round starting hole, which will be the approximate size of the first tooth of the broach. When internal keyways are cut, the starting hole will be the size of the horn – which is the slotted bushing used to hold the keyway broaching tool.
The most common shape is the simple keyway. The horn is placed inside the piece part, and then the keyway broach is fitted into the slot in the horn and pulled through the part. The last tooth of the keyway broach will be to the exact size of the desired keyway.
Besides keyways, virtually any type of internal shape or form can be cut. When keyways are aligned around a hole, it forms a spline. The spline can be any number of teeth, and its tooth shape can be straight-sided, involute, or helical.
In addition to keyway, spline & hexagon broaches, we also offer other types of broaches listed below.
Types of Broaches
Specialty internal broaches include spiral teeth broaches – in which there is continuous engagement of the teeth, which reduces vibration or broach ‘chatter’. Burnishing broaches are used for finishing, and are often included as the last set of teeth on a larger broach. The same applies to burring broaches.
Broaches designed to cut external dimensions are known as surface broaches. Surface broaches can be used as simply as cutting an external flat on a valve stem, or as complex as cutting an entire keyway on a lock cylinder. No starting hole is required, because the broach tooling begins its cut from an external surface of the part. Surface broaches can be made out of a solid piece of steel, or with a multiple set of inserts. The insert methodology allows for several sets of tools to be maintained at a lower cost, and also the ability to change the configuration or size of the shape being formed.
There are many different types of surface broaches, including pine tree broaches, slot broaches, slab broaches and pot broaches. Contact us today!