A2 Stainless Button Head Bolts ISO 7380

Hex socket button head bolts in A2 stainless steel, with a low-profile domed head and an internal hexagon (Allen key) socket, similar to ISO 7380-1. Also known as button head screws, half round head screws or dome head bolts (technically "screws" under the ISO system, though commonly sold as bolts), they give a neat, snag-free finish wherever a fixing stays on show, and suit everything from delicate enclosure and electronics work through to general engineering, furniture and construction fixings. Choose from 48 sizes, M3 x 10mm to M10 x 100mm, in packs of 5 or 20.

How It Works
The rounded, shallow head sits close to the work surface and has no corners or edges to catch on, and it carries no head markings, for a clean, decorative look. Head diameter, head height and hex socket size all scale precisely with thread diameter, and the deep hex socket takes a standard Allen key: a 2mm key drives the smallest M3 size, rising through 2.5mm, 3mm and 4mm for M4, M5 and M6, up to 5mm for M8 and 6mm for M10. The socket gives a strong, secure drive that resists cam-out far better than a slotted or cross-head fastener.

Key Features

• Low-profile button head: a neat, unobtrusive domed head with no corners or edges, ideal where a tidy, low-snag finish matters
• Plain head without markings: a clean, decorative look on visible fixings
• Hex socket drive: excellent grip and torque transfer with a standard Allen key, reducing the risk of cam-out
• A2 stainless steel: strong resistance to rust and corrosion for long-lasting performance in indoor and outdoor use
• Fully threaded: ISO metric thread to ISO 965-1, tolerance class 6g, made to ISO 4759-1 tolerances
• Similar to ISO 7380-1: head and socket dimensions for every thread size are listed in the table below
• Wide size range: 48 diameter and length combinations from M3 to M10

Why A2 Stainless Steel
A2 stainless steel is a general-purpose austenitic stainless alloy prized for its excellent resistance to rust and corrosion in normal indoor and outdoor environments: garden furniture, external cladding, bathrooms and kitchens all benefit from its low-maintenance, hygienic finish. A2 is an excellent, cost-effective option for the vast majority of everyday fixing tasks.

Specification

Head and Socket Dimensions by Thread Size

Metric figures are shown first, with the imperial equivalent in brackets. Under ISO 7380-1 the button head carries at least 80% of the load capacity of its strength class.

Lengths Stocked by Thread Size

Typical Applications

• Furniture and joinery: a clean-looking fixing for flat-pack, cabinet and shelving assembly where visible fasteners need to look tidy
• Enclosures and electronics: the smaller M3 to M5 sizes suit equipment casings, control panels and instrument assembly
• General engineering and machine building: mid to larger sizes (M6 to M10) for brackets, guarding, jigs and light-to-medium mechanical assemblies
• Outdoor fittings: corrosion resistance suits garden structures, garden furniture, external fixtures and cladding
• Bathrooms and kitchens: a low-maintenance stainless fixing where moisture is part of everyday use
• DIY and maintenance: a versatile, corrosion-resistant fixing for general household and workshop repairs

Installation Guidance

Follow each step in order:

1. Choose the thread size and length for your fixing from the tables above.
2. Seat the matching hex key fully in the socket: 2mm for M3, up to 6mm for M10.
3. Tighten into a tapped hole or nut until the domed head sits down on the surface.

Common Questions

Which hex key do I need?
2mm for M3, 2.5mm for M4, 3mm for M5, 4mm for M6, 5mm for M8 and 6mm for M10.

Are they fully threaded?
Yes. These bolts are supplied as fully threaded fasteners as standard.

What else are they called?
Button head screws, half round head screws, dome head bolts or Allen key button head bolts.

What sizes are available?
48 sizes from M3 x 10mm to M10 x 100mm; every length for each thread size is listed in the table above.

What pack sizes are available?
Every size comes in packs of 5 or 20 bolts.