Flat head knurled nut description
1. Definition and structural features
Flat head rolling nut is a specially designed fastener, whose core structure consists of the following elements:
Flat head design: The top is a flat structure, which is different from the convex head of traditional hex nuts, making it easy to fit tightly with the surface of the workpiece, reducing space occupation, and avoiding interference with other components.
Rolling pattern: The outer surface of the nut is distributed with regular raised patterns such as straight lines, mesh patterns, or diamonds, which are formed through cold extrusion or rolling processes to significantly increase friction.
Internal thread structure: The internal processing has standard threads (such as M3, M4, etc.), which are matched with bolts/studs to achieve mechanical connection.
2. Core functional features
Anti loosening performance: When the rolling pattern comes into contact with fingers/tools, it enhances the tightening torque through friction, reducing the risk of loosening in vibration environments.
Tool free installation: It can be tightened by hand (with the use of specialized rolling tools for better results), suitable for scenarios that require quick assembly or maintenance.
Low height design: The flat head structure makes the overall height lower than the hexagonal nut, which is more advantageous in thin-walled parts or compact spaces.
High strength materials: commonly made of carbon steel (such as C1022), stainless steel (such as 304/316), or copper alloy, the surface can be galvanized, nickel plated, or blackened to enhance corrosion resistance.
3. Typical application scenarios
Electronic devices: used to fix PCB boards, chassis shells, etc., to avoid the risk of circuit board deformation or short circuit caused by traditional nut protrusions.
Precision instruments: replace hex nuts in optical equipment and medical devices, reducing space occupation and lowering disassembly difficulty.
Automotive industry: used for non load bearing parts such as interior parts and wire harness fixing, balancing fastening requirements and lightweight design.
Furniture manufacturing: applied to cabinet door hinges, drawer slides, and other parts, balancing aesthetics and functionality.
4. Key technical parameters
Thread specifications: covering metric standards such as M2 to M12, with some customized models supporting imperial systems (such as UNC/UNF).
• Height range: The thickness of the flat head is usually 0.5-0.8 times the nominal diameter of the thread (e.g. M4 nut height is about 2-3.2mm).
Torque requirement: The installation torque needs to be adjusted according to the material and the type of rolling pattern. The recommended value is generally 70% -85% of the standard hex nut.
• Surface treatment:
Galvanized (white zinc/blue zinc): improves salt spray resistance to 48-96 hours.
• Passivation treatment: Stainless steel models can enhance their resistance to pitting corrosion.
Dacromet coating: suitable for heavy-duty anti-corrosion scenarios (such as ship equipment).
5. Selection precautions
• Load capacity: The flat head structure results in slightly lower shear resistance compared to hexagonal nuts, which needs to be verified based on static/dynamic loads.
Installation tools: It is recommended to use electric/pneumatic tools with a roller flower adapter head, and it is recommended to wear anti slip gloves for manual operation.
Environmental compatibility: Special alloys (such as Inconel 718) or ceramic coatings should be selected for high temperature (>150 ºC) or highly corrosive environments.
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