Knurling is a manufacturing process in which a rough, patterned texture is created on the surface of a metal in order to provide a grip as well as for aesthetic purposes. Accomplished through the use of specialized CNC turning tools, knurled patterns are visually appealing and are often more easily gripped than smooth surfaces.

Best suited for softer metals such as aluminum and standard grade steel, frequently knurled objects include tool handles, metal flashlights, knurled nuts, knurled control knobs, barbell bars, metal shafts, knurled winged screws, mechanical pencils and metal tubes. Knurling is particularly useful when it comes to assembling a high precision part into a hole in a low precision part when the hole does not closely match the diameter of the high precision part.

The knurled pattern on the high precision part presses into the knurled walls of the low precision part and forges a connection that otherwise would not have been. In addition, knurling offers extensive manufacturing and repair applications that allow knurling companies to serve diverse industries such as electronics, automotive, construction, aerospace, telecommunications, fitness equipment and marine.

Most often conducted on a lathe, knurling is commonly achieved through the same automatic-feed mechanisms that are used to form screw machined products. Knurling tools are used in conjunction with the lathe and enable the embossing of the pattern. Embossing is the process of creating a three-dimensional design on a part or material.

There are four general knurling patterns: annular rings, straight, angular and diamond knurl. These knurling patterns can be used independently or in a combination. Annular rings are most often used when using a plastic mating component. While annular rings allow for easy mating, the ridges can make the components difficult to pull apart. A straight knurling pattern is also referred to as a linear knurl pattern and consists of a series of linear straight ridges. The straight ridges can also be formed into helical grooves referred to as a helical knurling pattern.

Angular knurling consists of straight ridges in an angular direction and is typically used in order to give extra traction to an external handle or other connective piece. The most common type of knurling pattern for hand grips is diamond knurl because it creates the most traction between a user’s hand and the handle. A diamond knurl consists of a criss-cross pattern of ridges.

Knurling Informational Video