M3 Countersunk Hex Socket Aluminum Anodized Machine Screws — 10 Colors, 5–50 Pcs

A general rule: the screw length should equal the thickness of the material being fastened plus enough thread engagement in the receiving part — typically 1.5× the screw diameter (so at least 4.5mm for M3). For countersunk screws, measure from the top of the countersink to the tip. Available lengths range from 6mm (≈1/4") to 30mm (≈1-3/16"). For example, fastening two 5mm aluminum plates would typically call for a 10mm (≈3/8") screw.

Aluminum alloy screws are generally lighter and more corrosion-resistant than steel, but have lower tensile strength. They are typically suitable for light-duty fastening in electronics, RC models, camera rigs, and decorative assemblies where weight savings and appearance matter more than maximum load capacity. For high-stress or structural joints, stainless steel M3 screws are generally recommended.

The anodized coating provides a layer of corrosion resistance, making these screws generally suitable for light outdoor or humid-environment use — such as outdoor electronics enclosures or garden equipment panels. However, for prolonged exposure to saltwater, road salt, or harsh chemicals, stainless steel fasteners are typically recommended for longer service life.

These screws follow the ISO metric thread standard (M3 × 0.5mm pitch), which is the most common M3 thread pitch worldwide. They are compatible with standard M3 hex nuts, nylon lock nuts, brass threaded inserts, and any M3-tapped hole following ISO 68-1 specifications. They are not compatible with UNC/UNF inch-standard threads.

M3 hex socket countersunk screws typically require a 2mm hex key (Allen wrench). We recommend using a quality ball-end hex driver for better access in tight spaces. Avoid using worn or undersized keys, as aluminum sockets can strip more easily than steel under excessive torque.

Yes — anodized aluminum M3 countersunk screws are widely used in FPV drone frames, RC car and truck chassis, electronics enclosures, and camera cage assemblies. The countersunk head provides a flush, aerodynamic profile, and the anodized color options allow color-coding by screw length for faster assembly and maintenance. They are a popular choice for carbon fiber and aluminum frame builds.

Anodizing is an electrochemical process that converts the surface of the aluminum into a durable oxide layer — the color is integrated into this layer, not applied on top like paint. In normal use, the finish is generally resistant to chipping and fading. Heavy abrasion, contact with strong acids or alkalis, or repeated over-torquing can affect the finish over time. Avoid using power tools at high speed without torque control.