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When a standard socket cap head sticks out too far — snagging cables, fouling panels, or simply looking wrong — a button head screw is the right tool. These M1.6 to M5 round pan head hex socket screws give you the torque control of an Allen drive with a smooth, low-profile dome head that sits close to the surface without protruding. Whether you're assembling a 3D printer frame, mounting electronics in an enclosure, or fastening marine hardware, the right micro-fastener makes all the difference.
Every screw is machined from A2-70 (304) stainless steel — corrosion-resistant, oxidation-resistant, and suitable for both indoor and outdoor use. Sizes range from M1.6 through M5 with thread pitches of 0.35mm (M1.6) to 0.8mm (M5). All screws are fully threaded, with length measured from under the head to the tip. Available in lengths from 3mm to 150mm depending on size — select your exact size and quantity from the variant options above.
Ideal for 3D printer frames and enclosures, electronics and PCB mounting, RC models and drones, marine and outdoor hardware, furniture assembly, and any precision application where a low-profile, corrosion-resistant fastener is required.
M3 and M4 button head screws are the standard fastener for most 3D printer frames, extruder mounts, and enclosure panels — the low profile keeps moving parts clear and cables unobstructed.
M2 and M2.5 sizes handle PCB standoffs, panel mounts, and enclosure assembly where a flush, snag-free head is essential for clean builds and cable management.
A2 stainless steel resists saltwater corrosion and UV degradation — suitable for boat fittings, outdoor enclosures, and coastal installations where standard steel screws would rust.
M1.6 and M2 screws handle the smallest fastening needs in RC frames, drone arms, and precision instruments where weight and profile matter as much as holding strength.
| Material | A2-70 (304) Stainless Steel |
|---|---|
| Head Style | Button Head (Round Pan Head / Dome Head) |
| Drive Style | Hex Socket (Allen Key) |
| Thread Sizes | M1.6, M2, M2.5, M3, M4, M5 |
| Thread Pitches | M1.6 – 0.35mm / M2 – 0.4mm / M2.5 – 0.45mm / M3 – 0.5mm / M4 – 0.7mm / M5 – 0.8mm |
| Hex Key Sizes | M1.6 & M2 – 1.27mm / M2.5 – 1.5mm / M3 – 2.0mm / M4 – 2.5mm / M5 – 3.0mm |
| Thread Type | Fully threaded (length measured under head) |
| Length Range | 3mm–150mm (varies by diameter — see variant options) |
| Measurement System | Metric |
| Tensile Strength | Approx. 700 MPa (A2-70 grade) |
| Corrosion Resistance | Excellent — suitable for outdoor, humid, and coastal environments |
| Thread (M) | Head Dia. (dk) | Head Height (k) | Hex Socket (s) |
|---|---|---|---|
| M1.6 | 2.6 mm | 1.1 mm | 1.27 mm |
| M2 | 3.5 mm | 1.2 mm | 1.27 mm |
| M2.5 | 4.6 mm | 1.4 mm | 1.5 mm |
| M3 | 5.5 mm | 1.5 mm | 2.0 mm |
| M4 | 7.5 mm | 2.0 mm | 2.5 mm |
| M5 | 9.5 mm | 2.5 mm | 3.0 mm |
For button head screws, length is measured from the underside of the head (the flat bearing surface) to the tip — the head itself is not included. So an “M4 × 10mm” screw has 10mm of threaded shaft below the head. All lengths in this listing follow this standard metric convention.
Yes — all screws in this range (M1.6 to M5) are fully threaded from under the head to the tip, giving you maximum grip in blind holes or when using nuts. There is no unthreaded shank section.
A2 (304) stainless steel is highly corrosion-resistant and suitable for outdoor use in most environments — rain, humidity, and coastal areas. For continuous saltwater immersion, A4 (316) stainless is recommended, but for general outdoor and marine-adjacent applications, A2 performs excellently and will not rust under normal conditions.
M1.6 and M2 use a 1.27mm (0.05″) hex key; M2.5 uses 1.5mm; M3 uses 2.0mm; M4 uses 2.5mm; M5 uses 3.0mm. Always use a quality hex key that fits snugly to avoid rounding the socket recess.
Yes — these are standard metric machine screws. Use standard metric hex nuts of the same thread size and pitch (e.g., M3 × 0.5mm nut for an M3 screw). For outdoor use, pair with stainless steel nuts to avoid galvanic corrosion between dissimilar metals.
Both use a hex socket (Allen) drive, but button head screws have a wider, lower-profile dome head that distributes load over a larger surface area and sits more flush against the workpiece. Socket cap screws have a taller, narrower cylindrical head with higher clamping force. Button heads are preferred where a clean, low-profile appearance is needed or where clearance is limited.
This listing covers M1.6 to M5. We carry additional sizes in our store — please check our other listings or contact us for specific size requirements.
