Push Broach or CNC? Why Broaching Terminology Still Matters?

If you have worked with different shops, tooling catalogs, or older machining processes, you may have heard the term push broach used alongside broaching tool. While they are related, they are not always interchangeable depending on the process being used.

Understanding how this term is used helps avoid confusion when selecting tooling, reviewing prints, or discussing manufacturing methods.

What Is a Push Broach?

A push broach is a type of broaching tool designed to be forced through a part using a press or arbor. The tool contains multiple cutting teeth arranged along its length. Each tooth removes a small amount of material until the final shape is achieved.

Push broaches are commonly used for:

• Internal keyways
• Splines
• Polygon shapes

This method requires a dedicated broaching machine or press capable of applying consistent force through the entire stroke.

How Push Broaching Differs from CNC Broaching

Push broaching is a traditional process. The tool geometry is fixed, and the entire form is generated in one pass as the broach is pushed through the bore.

CNC broaching uses a different approach. Instead of a multi-tooth tool, a single insert cuts the form incrementally using controlled linear motion. The process is driven by the CNC program rather than by a mechanical press.

This difference changes how the operation is performed:

• Push broaching requires a secondary machine and full pass clearance
• CNC broaching can be completed in the same setup on a lathe or mill
• Push broaches are specific to one size and form
• CNC broaching uses indexable inserts that can be replaced or re-ground

While both methods produce internal features, the workflow and flexibility are very different.

Why the Terminology Overlaps

In some cases, the term broach is used generically to describe any tool that creates an internal form through a linear cutting action. Because push broaches were widely used long before CNC broaching became common, the terminology carried over.

This can lead to confusion when a print calls for a broach operation without specifying the method. One shop may assume a push broach, while another plans to complete the feature using CNC broaching on a lathe or mill.

Clarifying the process early helps avoid mismatched expectations.

Choosing the Right Method

Push broaches are still effective for high-volume production of standard forms where a dedicated machine is already in place. They are simple, repeatable, and capable of producing consistent results when the setup is fixed.

CNC broaching offers more flexibility. It allows shops to cut keyways and splines without additional equipment, reduces handling, and supports both through and blind hole applications.

For many modern machine shops, the ability to complete the part in one setup outweighs the speed advantage of traditional push broaching.

Clear Terminology Leads to Better Results

When discussing broaching, it is important to understand what process is being referenced. Push broaches are one type of broaching tool, but they are not the only option available.

Clear communication around tooling and method selection ensures that the correct process is used from the start, reducing delays and improving overall part quality.

If you are reviewing prints or evaluating how to produce internal features, confirming whether the operation requires push broaching or CNC broaching is a simple step that can prevent unnecessary complications.