Through Bolts Wall Expansion Anchor Bolts A2 304 A4 316 Stainless Steel

A2 (304) stainless steel contains 18% chromium and 8% nickel, providing good general corrosion resistance suitable for indoor, sheltered, and most outdoor environments. A4 (316) adds 2–3% molybdenum, which significantly improves resistance to chloride attack — making it the correct choice for coastal locations, swimming pool surrounds, marine structures, or anywhere exposed to de-icing salts or industrial chemicals.

The required embedment depth depends on the base material strength and the load being applied. As a general guide, the embedded portion of the anchor (below the fixture) should be at least 6–10× the thread diameter — for example, an M8 anchor typically needs 50–80 mm of embedment in concrete. Add the fixture thickness to determine the total bolt length needed. When in doubt, consult the load tables for your specific application or a structural engineer.

No. Sleeve expansion anchors rely on mechanical expansion against a solid bore wall to develop their holding strength. Hollow block, aerated concrete (AAC/Hebel), and similar low-density substrates do not provide sufficient resistance for the sleeve to expand against. For these materials, use chemical anchors (resin anchors) or specialist hollow-wall fixings instead.

The drill hole diameter should match the nominal anchor diameter: M6 → 6 mm bit, M8 → 8 mm bit, M10 → 10 mm bit, M12 → 12 mm bit, M16 → 16 mm bit, M20 → 20 mm bit. Use a carbide-tipped masonry or SDS drill bit and ensure the hole depth is at least equal to the anchor length plus 5–10 mm for debris clearance. Always blow or vacuum the hole clean before insertion.

Pack quantity varies by size and is shown in the Amount(pcs) variant selector above. Smaller, lighter sizes (M6, M8 short lengths) are available in packs of 2 or 3; larger sizes (M10 and above, longer lengths) are typically sold individually (1 per pack). Select your preferred size and quantity combination before adding to cart.

Sleeve expansion anchors can carry both shear and tensile loads, but overhead (pure tension) applications require careful attention to embedment depth and concrete strength. For safety-critical overhead installations — such as lifting points, overhead pipe hangers, or fall-arrest anchors — always verify the anchor's rated tensile capacity against your calculated load, apply an appropriate safety factor, and have the installation inspected by a qualified engineer.

Once set, the expansion sleeve deforms permanently against the bore wall and cannot be retracted. The bolt itself can be unthreaded and removed, but the sleeve remains in the hole. If you need to reuse the fixing point, you can re-insert a new bolt of the same diameter into the existing sleeve, provided the sleeve is undamaged and the hole is clean. For a completely clean removal, the sleeve must be driven deeper into the substrate or the hole re-drilled at a new location.