Knurlen

Knurlen is a mechanical manufacturing process used to create a textured pattern on a cylindrical surface. The resulting pattern provides improved grip and handling, and can also serve decorative purposes on tools, knobs, handles, and fasteners.

The process is typically performed on a lathe or with a dedicated knurling tool that carries hardened wheels. As the workpiece rotates, the tool is pressed against it with controlled feed. There are two primary methods: forming knurling, which displaces material to form raised ridges, and cutting knurling, which removes small amounts of material to form the pattern.

Common patterns are straight knurl and diamond knurl. Straight knurl consists of parallel rings, while diamond knurl creates an intersecting grid that resembles a diamond lattice. Diamond knurl generally provides better grip and may wear more evenly.

Materials commonly knurled include steel, stainless steel, aluminum, brass, and certain plastics, depending on tooling. Knurlen is often used on hand tools, bicycle or camera handles, pipes, valve stems, and fasteners with a knurled surface for grip.

Considerations include the diameter and surface finish of the workpiece, tool geometry, and alignment. Knurlen can induce residual stresses or affect concentricity if not performed correctly, and the pattern may be difficult to inspect with precision after assembly. Post-processing is sometimes used to deburr or clean the surface.

History and scope: Knurlen has been used in metalworking since the early 19th or 20th century, becoming a standard capability in machine shops. Modern knurling tools are widely available and can be used on a range of diameters and materials.