M2 and M3 Brass Hot Melt Copper Nuts – Outer Diameter 3.8mm/4.0mm/4.2mm for Plastic Embedding

When working with plastic components, stripped threads can ruin an assembly. These hot melt copper nuts provide a permanent, reusable threaded socket that is installed by heating and pressing into a pre-drilled hole. Made from brass and manufactured to the metric GB national standard, they offer consistent dimensions and reliable performance across a wide range of embedding applications. With eight distinct size variants covering M2 and M3 threads, outer diameters from 3.8mm to 4.2mm, and heights from 3.0mm to 6.0mm, there is a suitable option for most common plastic housing thicknesses.

Features and Construction

Each hot melt nut is precision-machined from brass with an untreated surface finish. The metric GB standard ensures that thread pitch and outer diameter tolerances are consistent, making them straightforward to integrate into existing designs or new projects.

Material and Build

The nuts are made entirely from brass, a material chosen for its good electrical conductivity, natural corrosion resistance, and ability to be heated and pressed into thermoplastics without excessive cooling shrinkage. The untreated surface maintains the natural brass colour, which is useful for visual identification of the embedded insert.

Size and Practical Fit

Select from eight styles: A through D are M2 thread with a 4.0mm outer diameter and heights of 3.0mm, 4.0mm, 4.5mm, and 5.0mm. Styles E through H are M3 thread with a 4.2mm outer diameter and heights of 3.0mm, 4.0mm, 5.0mm, and 6.0mm. The outer diameters of 3.8mm and 4.0mm (M2) and 4.2mm (M3) suit standard hole sizes for hot-staking into plastic.

Uses and Placement

These brass inserts are intended for embedding into thermoplastic materials where a strong, reusable thread is needed. The heat-and-press installation method creates a permanent bond without glue or additional fasteners.

Event or Professional Use

In manufacturing and prototyping environments, these nuts allow repeated assembly and disassembly of plastic enclosures, jigs, and fixtures without degrading the host material. The metric GB standard thread ensures compatibility with standard M2 and M3 machine screws.

Everyday Home Use

For hobbyists repairing or building plastic items such as electronics cases, 3D-printed parts, or household fittings, these inserts provide a robust solution. The 200- or 300-piece pack sizes offer a practical stock for multiple projects.

Benefits and Buying Value

Hot melt copper nuts reduce the risk of thread stripping in plastic, extending the life of the assembly. The range of sizes means you can select the right insert for the plastic thickness without modifying the design.

Reuse and Low Maintenance

Once installed, the brass insert can be unscrewed and re-screwed many times without wear, unlike threads tapped directly into plastic. The untreated brass surface does not require any special maintenance or coating.

Why Choose This Product

With eight size options, clear metric specifications, and pack quantities of 200 or 300 pieces, this range covers most common embedding requirements. The untreated brass finish and GB standard dimensions make them a straightforward choice for anyone who needs reliable threaded inserts in plastic.