What Is Knurling?
Last updated : 2026/7/28
Key Takeaways
Knurling creates textured surface patterns that improve grip, prevent slipping, and increase friction in press-fit assemblies.
The two main knurling patterns are straight and diamond, each designed for different grip and anti-rotation requirements.
Cutting knurling provides greater precision, while rolling knurling is faster and more economical for suitable materials.
What is Knurling?
Knurling is a machining process that creates textured patterns of fine ridges or grooves on a metal surface. By pressing a knurling tool against a rotating workpiece on a lathe, evenly spaced grooves are formed, and different patterns can be achieved by adjusting pitch, depth, and angle.
Knurling serves several purposes: it improves grip and prevents slipping, making it ideal for bars, handles, and knobs requiring precise adjustments. It also enhances friction in press-fit joints, helping prevent parts from shifting or loosening.
Types of Knurling
Straight Knurling (Flat Pattern)
Vertical grooves cut perpendicular to the circumference provide slip resistance and prevent rotational movement.
Diamond Knurling (Cross Pattern)
Diamond-pattern grooves around the circumference enhance grip and prevent rotation in all directions.
Knurling Methods
Knurling can be performed using two main methods: cutting and rolling.
Cutting knurling generally produces higher-quality, more precise patterns, while rolling knurling is faster and more cost-effective. Each method has its own advantages, so the choice depends on the specific application and requirements.
Cutting Type Knurling
In this method, the knurling tool cuts grooves directly into the workpiece. Compared with rolling, it places less load on the machine, though the workpiece diameter may become slightly smaller than the original material.
Rolling Type Knurling
In this method, the tool presses against the workpiece to raise the surface material without removing it. While no material is cut, some deformation of the workpiece can occur. This method is suitable only for materials with sufficient hardness and is generally not used for softer materials such as plastics.
Cutting Type Knurling | Rolling Type Knurling |
|---|---|
Places less load on the machine compared to rolling | Depending on conditions and the machine, may cause overload |
Cannot machine right up to a step if the workpiece has steps | Can machine right up to a step even if the workpiece has steps |
Cannot start machining from the middle section of the workpiece | Faster processing compared to cutting |
Workpiece diameter becomes smaller than the original material | Does not reduce the workpiece diameter |
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