Phillips Button Head Machine Screws — Steel M2 M2.5 M3 M4 M5 M6

A general rule of thumb: select a length equal to the thickness of the material being fastened plus 1–1.5× the screw diameter for thread engagement. For example, fastening two 3mm panels with an M3 screw typically calls for a length of 8–10mm (≈5/16–3/8"). When in doubt, size up — a slightly longer screw is easier to manage than a stripped short one. For blind tapped holes, the engaged thread length should generally be at least 1× the diameter for steel-into-steel, or 1.5–2× for softer materials like aluminum or plastic.

These screws are made from carbon steel. Carbon steel generally provides good tensile strength for indoor mechanical and electronic assembly applications. The finish helps provide a degree of corrosion resistance, though these are not intended for prolonged wet or outdoor exposure without additional protection.

These are carbon steel screws and are generally not recommended for prolonged outdoor or high-humidity exposure without additional corrosion protection (e.g., paint, sealant, or plating). For outdoor or marine applications, stainless steel variants are typically preferred. If you're unsure, contact us to confirm suitability for your environment.

Yes. These screws follow the ISO metric thread standard (M2, M2.5, M3, M4, M5, M6) with standard coarse pitch per diameter. They are compatible with standard metric nuts, threaded inserts, and tapped holes of the corresponding size. They are not compatible with UNC/UNF (inch) threads.

These screws use a Phillips (PH) cross drive. For M2–M3, a PH0 or PH1 bit is typically appropriate. For M4–M6, a PH2 bit is generally the right fit. Always match the bit size carefully — using an oversized bit can cam out and damage the head, especially on smaller M2–M2.5 screws.

Torque capacity varies by size and the specific material grade. As a general reference for carbon steel machine screws: M3 typically handles around 0.5–0.8 N·m, M4 around 1.2–2.0 N·m, and M6 around 4–6 N·m. For load-critical or structural applications, always verify against the manufacturer's specification sheet. Contact us if you need specific grade documentation.

Yes — Phillips button head machine screws are commonly used with plastic enclosures, aluminum chassis, and sheet metal when paired with the correct tapped hole or threaded insert (e.g., heat-set inserts for plastic). The low-profile button head is especially useful where clearance is limited or a flush-ish appearance is desired. Avoid overtightening in softer materials to prevent thread stripping.

Each size is available in packs of 10, 50, 100, 500, and 1000 pieces. Larger packs are priced at a lower per-piece cost, making them ideal for production runs, restocking a parts bin, or ongoing repair work. Simply select your size and quantity from the variant dropdowns above.