Alloy Metric Button Head Socket Cap Screws

Metric Alloy Button Head Socket Cap Screws — ISO 7380, Class 10.9

Shop Metric Alloy Button Head Socket Cap Screws

Metric alloy button head socket cap screws follow ISO 7380, which governs dimensions and mechanical requirements for metric low-profile socket cap screws. Class 10.9 alloy steel is standard, providing a minimum tensile strength of 1,040 MPa (~145,000 PSI). They are used in metric-designed machinery and equipment where a low-profile, internally-driven fastener is needed — including 3D printers, CNC equipment, robotics, and European-designed machinery. ISO 7380 button heads are not intended as direct substitutes for ISO 4762 socket head cap screws (SHCS) in high-load applications.

ISO 7380 vs. ISO 4762 — Key Differences

ISO 4762 covers standard metric socket head cap screws with a tall cylindrical head and deep socket engagement. ISO 7380 covers metric button head socket cap screws with a low dome head and shallower socket. The button head (ISO 7380) has a larger head diameter but shorter socket depth, which limits maximum installation torque compared to SHCS. Use ISO 7380 where low profile, clean appearance, or snag-free installation are the requirements — use ISO 4762 where maximum clamp load is needed.

Specifications

Standard: ISO 7380
Property Class: Class 10.9 (standard)
Tensile Strength: 1,040 MPa (~145,000 PSI) minimum
Drive: Internal hex (metric hex key — larger relative socket than inch button heads)
Finish: Plain or black oxide
Size Range: M3 through M12 in stock

Hex Key Sizes for Metric Button Head Cap Screws

Metric button head cap screws use a larger hex socket relative to thread diameter than inch-series button heads, providing better torque capacity in metric applications. Common metric pairings: M3 uses 2mm; M4 uses 2.5mm; M5 uses 3mm; M6 uses 4mm; M8 uses 5mm; M10 uses 6mm; M12 uses 6mm. These differ from metric SHCS (M6 SHCS uses 5mm, M8 SHCS uses 6mm) — verify hex key size for your specific fastener.

Frequently Asked Questions

What standard covers metric button head socket cap screws?
Metric button head socket cap screws conform to ISO 7380. Class 10.9 is the standard alloy property class, providing 1,040 MPa (~145,000 PSI) minimum tensile strength. ISO 7380 is distinct from ISO 4762, which covers standard metric socket head cap screws with higher socket engagement and clamp load capacity.

Can ISO 7380 metric button heads substitute for ISO 4762 socket head cap screws?
No — not in structural or high-load applications. ISO 7380 button heads have shallower socket engagement, which limits maximum installation torque compared to ISO 4762 SHCS. They are appropriate for light to moderate loads where low profile or appearance is a priority. Verify load requirements before substituting.

What hex key do metric button head socket cap screws use?
Metric button heads use a different hex key than metric SHCS of the same size. Common pairings: M5 uses 3mm, M6 uses 4mm, M8 uses 5mm, M10 uses 6mm, M12 uses 6mm. Metric SHCS use a larger key at most sizes (M6 SHCS uses 5mm). Always verify hex key size against the specific fastener to avoid socket rounding.

What property class are metric alloy button head socket cap screws?
Class 10.9 is standard for ISO 7380 metric alloy button head socket cap screws, providing 1,040 MPa (~145,000 PSI) minimum tensile strength. Class 12.9 is not standard for button heads — the button head socket form is not designed for the torque levels that Class 12.9 would require.

Metric alloy button head socket cap screws are commonly used alongside metric socket head cap screws in the same assembly — SHCS (ISO 4762) where high clamp load is needed, button heads (ISO 7380) where low profile or clean appearance is the priority. Metric flat washers and lock washers pair naturally with both. For corrosive environments requiring metric button heads, see metric stainless button head socket cap screws. For inch-series button head applications, see alloy steel button head socket cap screws (ASME B18.3). The full button head selection and all socket fastener types are available through the Button Head Socket Cap Screw and Sockets categories.