Knurling Professional Knowledge

Knurling refers to the regular patterned texture processed on the surface of shaft parts, handle parts and other mechanical components. Its core function is to increase surface friction, provide a comfortable grip and prevent slipping during operation.1. Classification of KnurlingKnurling is mainly divided into straight knurling and diamond knurling:
Straight knurling: Features axial straight lines on the surface.
Diamond knurling: Adopts crossed grain lines with a standard intersection angle of 30°.
2. Key Knurling ParametersThe main technical parameters of knurling teeth include the following four items:

Module (m)
It determines the specification of the knurling pattern. The larger the module, the coarser and deeper the grain, the larger the pitch, and the better the anti-slip performance. Common standard values: 0.2, 0.3, 0.4, 0.5.

Tooth height (h)
Knurling is formed by extrusion. After molding, the raised and recessed parts each have a height of h, and the total grain height is 2h.

Pitch (P)
It means the distance between the corresponding positions of two adjacent teeth. The relational formula with module:
(P=pi cdot m)

Fillet radius (r)
Transition fillet at the tooth tip and tooth root. It realizes smooth transition, reduces stress concentration and avoids hand scratching.

3. Differences & Application Selection: Straight vs Diamond Knurling3.1 Marking Standard (GB 6403.3—1986)
Straight knurling: Straight knurling m0.3
Diamond knurling: Diamond knurling m0.3
3.2 Anti-slip Performance
Straight knurling: Unidirectional anti-slip, only provides axial anti-slip effect.
Diamond knurling: Bidirectional anti-slip, effective in both axial and circumferential directions.
3.3 Processing Technology
Straight knurling: Single-direction rolling, simple processing and low cost.
Diamond knurling: Requires bidirectional rolling, complex craftsmanship and higher processing requirements.
3.4 Application Scenarios
Straight knurling: Suitable for parts that only need axial limiting and basic anti-slip, such as simple shaft sleeves and non-rotating handles.
Diamond knurling: Ideal for parts requiring manual twisting, frequent rotation and stable gripping, such as knobs, adjusting handles and special nuts.