Source: Flickr

Even if you haven’t heard of knurling, you have most likely seen a product with a knurled grip. They’re often used on hand tools such as screwdrivers, wrenches, and other tools. Knurling is a finishing process in part manufacturing that’s used to create a distinct pattern across the material surface that provides a better grip and enhances the aesthetics of the workpiece.

Knurling Operation

Knurling is a lathe machining application that can involve either subtractive manufacturing or cold working. The former means that the knurling tool is cutting away the material to form the knurled pattern ridges, meaning that the blank diameter remains the same.  However, the cold-forming knurling process relies on material displacement to form a textured, non-slip pattern.

A knurling tool, called a knurling wheel, is pressed hard against the rotating workpiece, forcing the material to conform to the tool’s pattern. This results in a raised pattern on the pressed object, which slightly increases the diameter of the workpiece.

Wheel knurling tools are typically carbide steel wheels with serrated or knurled edges that are rolled over the surface of the workpiece, creating a desired pattern. Most applications rely on a diamond knurl pattern as it provides an ideal gripping surface.

Knurling Patterns

While their primary purpose is to enhance the grip and aesthetic of a component that’s being knurled, different patterns have different applications. Here’s a short breakdown of each pattern:

• Diamond Pattern — This type of knurling features both left and right diagonal knurls and it’s mainly used to prevent slippage and enhance grip. It’s mostly used in knobs, torque handles, weightlifting barbells, and hand tools.
• Straight Knurling — Straight knurling produces a straight horizontal or vertical pattern across the workpiece surface, which is great for increasing the surface area of the workpiece or improving grip.
• Right-Hand Knurling — Right-hand knurling is the second most used knurling type next to the diamond shape pattern. It’s a diagonal pattern sloped to the right for a more comfortable grip for right-handed clamping or tightening applications.
• Left-hand Knurling — Similar to right-hand knurling in function, but it’s significantly less common.

Knurling Applications

Source: Flickr

Knurling is used to create a better gripping surface and/or to create a decorative effect in a wide range of applications. Its most common applications include handles and grips on various tools and machinery. This significantly reduces the chances of slippage and potential injury. Additionally, the casings of various connectors are knurled to provide a better grip.

Knurling is often used as a decorative feature on jewelry, watches, and other accessories, as it provides an aesthetically appealing surface. Lastly, it’s often used on threaded fasteners, such as thumb screws, to provide a better grip for fastening.

Knurled Knobs and Handles

Knurling is most commonly used to treat various surfaces and provides them with more tractive and aesthetically appealing surfaces. If you want to learn more about knurling, work holding, and fasteners, visit Reid Supply. Don’t forget to check out our extensive online library of professional literature and engineering handbooks.