Hot‑melt copper nuts (also called heat‑insert nuts, insert nuts, or pre‑molded nuts) are copper fasteners that are heated and pressed into plastic parts. They are widely used in electronic device housings, plastic components, automotive interior parts, home appliance shells, and any application where a threaded connection needs to be embedded into a plastic substrate.

We mainly use C3604 brass. This material offers excellent thermal conductivity, corrosion resistance, and mechanical strength, ensuring reliable performance over a long service life in various working environments.

Common installation methods include hot‑melt embedding, ultrasonic embedding, and injection‑molding pre‑placement. Hot‑melt embedding is the most popular: the nut is heated to soften the surrounding plastic, then pressed vertically into the pre‑drilled hole. For best results, use a hot‑melt machine or a soldering iron, keep the nut perpendicular during insertion, and hold it in place for 2‑3 seconds to allow the plastic to re‑flow and cool.

The double‑diagonal knurling or groove pattern increases friction with the plastic substrate after embedding, which significantly improves the joint’s stability and helps prevent loosening or thread stripping during use.

We can produce nuts ranging from M1.2 to M8 in thread size, with custom dimensions (inner diameter, outer diameter, overall height, etc.) available upon request. Common examples include M3×5.5×4, M5×5×6.5, M6×9.5×9.5, and M8×15×10.

They are widely used for PCB board mounting and spacing in electronic equipment, mechanical structural connections and height adjustments, as well as supporting and fixing internal components such as motherboards and power supplies inside chassis. They are also used in steel‑structure connections in construction.

We offer several material choices:

Brass – good corrosion resistance, mechanical strength, and electrical conductivity.

304/303 stainless steel – excellent corrosion and heat resistance, high strength, and rust‑proof.

Carbon steel – can be surface‑treated (e.g., blue‑white zinc plating) for corrosion protection.

Nylon 66 (PA66) – UL94 V‑2 flame retardant rating, with excellent insulation properties.

We produce single‑ended hex standoffs, double‑ended studs, hollow hex standoffs, and male‑female standoffs. The single‑ended hex design allows easy tightening with a hex wrench; hollow types are useful for cable routing or weight reduction.

Important points:
① Use the correct size hex wrench and avoid excessive force that could deform the standoff or strip the threads.
② Apply force along the axis of the screw – do not tilt the wrench.
③ Store in a dry, well‑ventilated area to prevent surface oxidation caused by humidity.

Typical thread sizes include M3, M4, M5, M6, M8, and M10. The hex‑width across flats varies with the thread size. Custom lengths can be produced to your requirements.

The two most common sizes are #6‑32 UNC (imperial, about 3.5 mm diameter) and metric M3. Lengths typically range from 6 mm, 30 mm, 35 mm, etc., depending on the fan and chassis thickness.

Common materials include carbon steel (strong and durable) and stainless steel (better rust resistance). Surface finishes like nickel plating improve corrosion protection and give a satin appearance.

Length depends on the total thickness to be fastened. As a general rule: for a 25‑mm thick fan, use 30‑mm long screws; for a 30‑mm thick fan, use 35‑mm long screws. Be careful not to use screws that are too long, as they may penetrate the radiator fins of the cooling system.

The most common sizes are metric M3 and imperial #6‑32 UNC. #6‑32 UNC is typically used for 3.5‑inch hard drives, motherboards, and case panels; M3 screws are used for 5.25‑inch optical drives, 3.5‑inch floppy drives, and 2.5‑inch hard drives; #4‑40 UNC is often found near DVI, VGA, and other interface connectors.

Although the diameters are similar, the thread pitches are different – they are not interchangeable. Using the wrong type will almost certainly cause thread damage or stripping. Always confirm the correct specification before installation.

We supply #6‑32 UNC, M3, M2, single‑pass hex brass standoffs, KB5 screws, and more. For motherboard mounting, we also offer pan‑head screws with a flanged skirt.

We are a direct manufacturing factory with our own production lines and a complete quality control system – no middleman mark‑up.

Yes. We welcome custom orders based on drawings or samples, including special shapes, materials, and sizes. As an original factory, we offer competitive pricing and shorter lead times, especially for large‑volume or urgent orders.

You can contact us by phone, email, or online channels with your product specifications or drawings. We usually respond with a quotation within 12‑24 working hours. For urgent requests, please call us directly.

For standard stock items, MOQ can be negotiated. For custom products, the MOQ depends on the specific size, manufacturing complexity, and raw material availability. Please contact us for details.

We possess comprehensive testing equipment: XRF spectrometers for incoming material verification, video measuring systems for dimensional inspection, push-pull testers for mechanical property testing, micro-hardness testers for hardness checks, and constant-temperature electric drying ovens for sample "pretreatment." Fully automated CCD visual inspection systems ensure 100% inspection of finished products. Additionally, our robust warehouse management system guarantees efficient delivery.