8461.40 - Gear cutting, gear grinding or gear finishing machines:

This HTS category, 8461.40, encompasses specialized machine tools designed for the precise shaping and finishing of gears. These machines are critical in manufacturing processes where the accuracy and quality of gear teeth are paramount. They are specifically engineered to perform operations such as cutting new gear teeth into blanks, grinding existing teeth to achieve tighter tolerances and superior surface finish, or applying finishing touches to enhance performance and longevity.

Unlike its sibling categories within 8461, which cover shaping, slotting, broaching, sawing, or cutting-off machines, this heading is exclusively dedicated to gear-specific machining. While other machines in this section might cut metal, only those within 8461.40 are built with the specialized tooling, complex indexing mechanisms, and precise motion control required for gear geometry. For instance, shaping machines produce gear teeth through a reciprocating cutting action, while broaching machines use a multi-tooth cutting tool to remove material sequentially. This category, however, focuses on machines that specifically generate or refine the distinct profiles of gears.

The subcategories within 8461.40 further delineate these specialized machines based on their primary function. 8461.40.10 covers gear cutting machines, which create the initial gear tooth profiles from a blank. Following the cutting operation, machines classified under 8461.40.50 are employed for gear grinding or finishing. Grinding machines use abrasive wheels to remove small amounts of metal, achieving extremely high precision and surface finishes, while finishing machines might employ different techniques like honing or lapping to impart the final desired characteristics to the gear teeth.