M8 Bolts

M8 Bolts — High-Tensile Metric Fasteners for Trade and Industry

M8 bolts are one of the most frequently specified metric fastener sizes in Australian trade and industry. With an 8 mm nominal diameter and a standard coarse pitch of 1.25 mm, M8 strikes the ideal balance between compact size and genuine load-carrying capability — strong enough for structural connections in light machinery, light enough to be used throughout automotive, agricultural, and general engineering assemblies. AIMS Industrial stocks the full M8 bolt range in Grade 8.8 high tensile and stainless steel, including hex head, socket cap, coach, eye bolt, T-bolt, and anchor bolt styles, dispatched from our Sydney warehouse.

Types of M8 Bolts

M8 hex head bolts (AS 1111.1 / ISO 4014 and ISO 4017) are the standard wrenching fastener, driven with a 13 mm spanner or socket. These are the default choice for most bolted connections in steel and aluminium structures. M8 socket cap screws (ISO 4762) use a 6 mm hex key drive and deliver higher clamp loads than a hex bolt of the same size — preferred in precision machinery, tooling, and confined-space installations. M8 countersunk socket screws sit flush with the parent material; button head socket screws provide a low-profile domed finish. M8 T-bolts slide into aluminium extrusion T-slots and are widely used in modular framing, machine guarding, and workholding systems — one of the most searched M8 variants in Australia. M8 coach bolts are used in timber-to-timber and timber-to-steel connections, their square neck preventing rotation during tightening. M8 eye bolts provide a lifting or rigging attachment point rated for the specific WLL on the bolt. M8 anchor bolts and rawl bolts are used to secure plant, equipment, and structural elements into concrete.

Grades and Materials

Grade 8.8 M8 bolts have a tensile strength of 800 MPa and are the standard for engineered fastening in steel-to-steel applications. They are typically zinc-plated for general corrosion protection. Where higher strength is required — in automotive, tooling, or clamping applications — Grade 10.9 M8 socket cap screws (1,040 MPa tensile) are available. For corrosive, marine, or food-grade environments, M8 stainless steel bolts in A2-70 (304) or A4-80 (316) are the correct specification. Galvanised M8 bolts are used in outdoor structural and civil applications where hot-dip coating provides long-term protection. High tensile M8 bolts are commonly called for in automotive engine and chassis work, agricultural machinery, and engineering plant.

Dimensions and Thread Data

Standard M8 coarse pitch is 1.25 mm. Fine pitch M8×1.0 is available for applications requiring finer adjustment or higher vibration resistance in thin materials. Key dimensions: hex head across-flats is 13 mm; socket cap screw hex key drive is 6 mm; standard lengths range from 10 mm to 200 mm for hex bolts and 8 mm to 100 mm for socket cap screws. Thread engagement should be a minimum of 1.0×D (8 mm) in steel and 1.5×D (12 mm) in aluminium or cast iron for full load capacity.

Applications

M8 bolts appear across virtually every industrial sector: automotive and transport (suspension components, brackets, body panels), agricultural machinery (implements, guards, linkages), general fabrication and structural steelwork, machine building and maintenance, conveyor systems, mining equipment, HVAC and plant room equipment, and modular aluminium framing systems. M8 stainless bolts are the standard in food processing, beverage, dairy, marine, and laboratory equipment. T-bolts in M8 are ubiquitous wherever aluminium profile framing (80/20, Bosch Rexroth, RKRose+Krieger) is used.

Choosing the Right M8 Bolt

Select head style based on wrenching access (hex for open access; socket cap for recessed or torque-critical positions), grade based on load and environment (8.8 zinc for general; 10.9 for high-clamp; A4 stainless for corrosive), and length based on material stack plus engagement. Always use the matching M8 nut (ISO 4032) and washer (ISO 7089) — do not mix property classes. For safety-critical applications including lifting eyes, confirm the rated WLL is stamped on the fastener before use. The AIMS team can help you specify and price for any quantity.

AIMS Industrial stocks M8 bolts, socket cap screws, T-bolts, eye bolts, coach bolts, and anchor bolts in Grade 8.8, Grade 10.9, 304 and 316 stainless steel, and galvanised steel. Order online or contact our Sydney team for trade pricing and fast Australia-wide delivery.