What is broaching?

Broaching is a machining process used to cut internal or external shapes by pushing or pulling a specially designed tool called a broach across a workpiece. Unlike traditional cutting tools that may require multiple passes or secondary operations, a broach tool removes material in a single, progressive motion. Each tooth on the broach is slightly larger than the one before it, so the tool gradually shapes the part until the final profile is reached.

This process is most commonly used to create features such as keyways, splines, hexagonal holes, or custom slots that provide torque transmission and alignment in mechanical assemblies. Because of its accuracy and repeatability, broaching is valued in industries that require tight tolerances, like aerospace, automotive, medical, and heavy equipment manufacturing.

Broaching has traditionally been done on large, dedicated machines, but advancements in tooling now make it possible to perform the same operation directly inside CNC mills and lathes. CNC Broach Tools pioneered this innovation, creating patented tools and methods that brought broaching into the CNC environment. This allows shops to integrate broaching into their existing machining workflow without outsourcing or purchasing specialized equipment.

How broaching works

A broach tool has a series of progressively larger teeth that cut in sequence as the tool is pushed or pulled through the material. Each tooth removes a small amount of stock, resulting in an accurate and consistent final profile. With CNC broaching, machinists can perform these operations directly on mills and lathes without secondary setups, reducing time and increasing efficiency. CNC Broach Tools do not have multiple teeth and cut by programming multiple passes.

Why broaching is important

Broaching is essential for creating shapes that provide strength, alignment, and torque transmission in mechanical assemblies. Common examples include:

• Keyways in gears and pulleys
  
• Splines in shafts and hubs
  
• Hexagonal holes for fasteners
  
• Custom shapes for specialized applications
  

The role of CNC Broach Tools

CNC Broach Tools was the first to introduce broaching inside standard CNC machines. With patented tooling, proven programming strategies, and expert technical support, the company enables shops of all sizes to produce high-quality internal forms quickly and reliably. Contact CNC Broach Tools to learn how we can help with your next project.