M6 M8 Galvanized Expansion Bolts — Metal Impact Anchors for Concrete & Masonry

As a general rule, the bolt length should be at least 3–4× the bolt diameter plus the thickness of the material being fastened. For example, an M6 bolt securing a 10mm bracket into concrete would typically need at least a 40mm (≈1-9/16") bolt. When in doubt, size up — a longer embedment depth generally means a stronger hold. For structural or overhead applications, consult a licensed engineer.

Load capacity depends on bolt size, concrete strength, and embedment depth. In standard concrete (C20/25), M6 expansion anchors typically support tensile loads in the range of 1–2 kN, while M8 anchors generally handle 2–4 kN. Shear capacity is typically higher. These figures are general estimates — for load-critical or life-safety applications, always have a structural engineer specify the correct anchor and verify pull-out values for your substrate.

Yes, in most cases. The galvanized zinc coating provides meaningful corrosion resistance for outdoor, humid, and intermittently wet conditions — such as exterior wall brackets, fence hardware, or covered patio structures. For fully submerged installations or highly corrosive environments (coastal salt air, chemical exposure), stainless steel anchors are generally the more appropriate choice.

These bolts use standard ISO metric coarse threads: M6 at 1.0mm pitch and M8 at 1.25mm pitch. They are compatible with any standard metric hex nut, flat washer, or threaded insert of the matching size. No proprietary hardware is required.

These metal impact anchors are designed for solid, dense substrates — primarily poured concrete, solid brick, and dense concrete masonry units (CMU). They are generally not suitable for hollow block, lightweight aerated concrete (AAC), drywall, or soft substrates without additional anchoring hardware. If you're unsure about your substrate, contact us before ordering.

Each listing offers 2, 5, 10, 20, 25, 50, or 100 pieces per order — just select your preferred quantity from the variant options. Larger packs (50–100 pcs) offer the best per-unit value and are popular with contractors, maintenance teams, and anyone running a multi-fixture installation. There's no minimum order requirement.

Installation requires a hammer drill with a carbide-tipped masonry bit sized to match the bolt diameter (M6 → 6mm bit; M8 → 8mm bit), and a standard wrench or socket set to tighten the hex nut. Drill to the required embedment depth, clear the hole of dust, insert the anchor, pass the bolt through your fixture, and tighten until the sleeve expands and locks. No specialty tools are needed.