Metal Bolt Caps

Metal bolt caps are protective components that cover the exposed part of the bolt head or nut. They are commonly stamped and formed from mild steel, stainless steel or aluminum alloy. They are equipped with elastic anti-slip washers or bump structures inside, which can closely fit the hexagonal surface of the bolt. According to ASTM B117 salt spray test standard, when the cap adopts hot-dip galvanizing process and the thickness of the zinc layer is not less than 12 microns, it can withstand 720 hours in a neutral salt spray environment without red rust on the matrix. This is nearly three times longer than the corrosion resistance time of ordinary painted caps. At the same time, the outer wall of the cap is often rolled with a diamond pattern, which is easy to tighten manually or disassemble with special tools. It is widely used in outdoor guardrails, mechanical equipment and rail transit to prevent rain, oil and dust from invading the thread pair, thereby effectively delaying corrosion and sticking.

 

 

In a dynamic load environment, the fastening retention and vibration resistance of the cap are particularly critical. According to the test regulations for anti-loosening fasteners in DIN 267 Part 28, when the cap has a built-in nylon locking ring and is subjected to sinusoidal vibration excitation with a frequency of 30 Hz, after two million cycles, the axial displacement of the cap relative to the bolt is still less than 0.5 mm, proving that it can effectively maintain the bolt's pretightening force without attenuation due to continuous vibration. At the same time, the top of the cap can be designed as a flat top or a spherical crown to adapt to different installation spaces. Its impact resistance is also excellent. After a 500-gram steel ball was dropped from a height of one meter, the cap body had no cracks and the claws were not deformed. It can withstand an impact energy of about five joules. These characteristics make metal bolt caps an ideal accessory with both protection and anti-loosening functions in scenarios such as power towers, construction machinery, and outdoor lighting. They also significantly reduce the frequency and labor costs of regular maintenance.

 

 

 

 

 

 

Get drawings from customers, or design drawings according to customers' detail requests or sample.

The two parties confirm the details of the drawings and product raw materials, surface treatment, etc.

 

 

 

 

Quote and confirm order quantity, specify all the details including trade terms, payment terms, type of package, etc.

 

 

 

Design and Make tooling according to the confirmed drawing, do the modification if needed while testing.

 

 

 

Make first samples and inspect them according to the drawing strictly.

Send to the customer for approval after internal approval.

 

 

 

Strictly produce the goods as per the drawings and first samples.

Packed well after final inspection and ship to customers.

 

 

 

 

 

 

 

 

 

 

 

 

 

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