Broaching practice: Are push broaches used only for sizing holes, or can they also generate the hole profile?

Introduction / Context:Broaching is a multi-tooth process in which each successive tooth removes a small increment of material. A common misconception is that a push broach merely “sizes” a pre-formed hole. In practice, both push and pull broaches may be designed with roughing and finishing sections to generate the target geometry directly.

Given Data / Assumptions:

• Through-holes or short blind holes in ductile materials.
• Proper starting hole (pilot) provided for chip accommodation and guidance.
• Broach design includes roughing teeth, semi-finishing teeth, and finishing lands.

Concept / Approach:Push broaches are typically shorter and used on small parts, arbors, or press broaching. They commonly include cutting tooth rise to remove stock and a finishing section that brings the hole to size and form (e.g., keyway, polygon). Limiting them to “sizing” ignores the engineered progression of teeth that actually creates the final geometry.

Step-by-Step Solution:

Verification / Alternative check:Tool catalogs illustrate push broaches with full tooth sequences and chip breakers intended for geometry generation, not merely calibration of size.

Why Other Options Are Wrong:Material or hole type does not fundamentally restrict a push broach to sizing. Pull-broaching is more common for long holes, but push broaches still cut, not just size.

Common Pitfalls:Insufficient pilot hole or chip space causing jamming; misjudging the press tonnage needed because roughing teeth remove stock incrementally.

Final Answer:Incorrect — push broaches can rough and finish to generate size and form