Gear Knurling

a process of forming or machining gear teeth, gear racks, and worms by means of plastic flow of the metal rather than the removal of shavings. A distinction is made between shaping knurling and hardening knurling. In shaping (the shaping of the gear teeth directly on cast, forged, and stamped blanks), the gears are formed on a knurling mill after the blank is heated (usually with high-frequency cur-rents) or without heating (for gears with small moduli). Gear-knurling mills may have axial or radial feed. Axial feed ensures higher precision of the gear but is somewhat less productive. The use of gear-knurling machines makes rough and sometimes even final gear cutting unnecessary. Hardening knurling (partially or over the entire surface of the gear teeth) involves the treatment of preformed teeth by surface areal deformation to increase their resistance to fatigue and wear and to increase their service life. The process is per-formed on special gear-knurling mills.

Gear knurling is done with a gear-knurling tool (knurl) that operates according to the generation method or rollers or shaped disk rolls that operate according to the template method. The material in the tool is usually chromium, chromium-nickel, or chromium-vanadium steel.