M10 Stainless Steel Square Head Bolts — A2 304, Plain Finish, 16mm to 100mm

Generally, the bolt length should equal the total thickness of the materials being joined, plus allowance for a nut and washer. For M10 bolts, a typical rule is to add 15–20mm beyond the clamped material. Available lengths range from 16mm (≈5/8") to 100mm (≈3-15/16"). If you are unsure, choose the next size up — you can always use a washer to take up slack.

A2 (AISI 304) stainless steel bolts are typically rated to a tensile strength of around 500–700 MPa, with a proof load stress of approximately 380 MPa for M10 fasteners per ISO 3506. They are generally suitable for light-to-medium structural loads. For heavy structural or high-vibration applications, consult an engineer.

Yes. A2 304 stainless steel offers good corrosion resistance in most outdoor environments, including rain, humidity, and mild coastal conditions. For highly aggressive marine or chloride-rich environments, A4 316 stainless steel is generally recommended. These bolts are a solid choice for garden structures, outdoor furniture, fencing, and general exterior fastening.

These bolts use ISO metric coarse thread (M10 × 1.5mm pitch), which is the standard thread for M10 fasteners worldwide. They are compatible with any standard M10 metric nut, washer, or threaded insert. They are not compatible with UNC/UNF inch-standard hardware.

Square head bolts are typically tightened with an adjustable wrench, open-end wrench, or pipe wrench gripping the flat sides of the head. They are not designed for socket or hex key drive. The square head profile provides a large bearing surface that resists rounding under high torque — a practical advantage in timber and structural applications.

Yes. Square head bolts are traditionally used in timber framing, barn construction, and heavy woodworking because the large square head distributes clamping load over a wider area and resists pull-through. They are also commonly used in decorative applications where a vintage or industrial aesthetic is desired. Pre-drilling a clearance hole is recommended for clean installation.

Stainless steel can cause galvanic corrosion when in direct contact with dissimilar metals such as aluminum or carbon steel in wet environments. In most cases, using an insulating washer or anti-seize compound between the bolt and the dissimilar metal will mitigate this risk. For aluminum structures, consult material compatibility guidelines before installation.