M10 Hex Head Coach Screws DIN 571

M10 hexagon head coach screws manufactured to DIN 571. Also known as lag screws, lag bolts or hex head wood screws, these heavy-duty fasteners use a hexagon head rather than a slotted or recessed drive, so they can be tightened with a standard spanner or socket for far higher torque than a screwdriver allows, ideal wherever a strong, dependable heavy-timber fixing is needed. The design needs no nut on the reverse face: the coarse wood-screw thread draws directly into the timber (or, with a wall plug, into masonry), making these a practical choice wherever there's no way to get behind the fixing to hold a nut in place.

Manufactured from carbon steel and finished with a bright zinc-plated (BZP) coating, these screws offer reliable general-purpose corrosion resistance.

The coarse, deep wood-screw thread is engineered to bite directly into timber, generating strong pull-out resistance without requiring a nut on the reverse side, making these screws well suited to structural and semi-structural heavy-timber connections such as decking subframes and railway sleeper landscaping. Used together with a suitable wall plug, the same hex-head design can also be driven into brick, block or concrete.

Key Features

• Manufactured to DIN 571: head, drive and thread dimensions follow the DIN 571 standard across every length.
• Hexagon head drive: tightened with a standard 17mm (0.67in) spanner or socket rather than a screwdriver, allowing far higher installation torque for a firmer, more dependable fixing.
• Carbon steel construction: a robust base material, built for durability and resistance to loads, suited to structural and semi-structural timber connections.
• Bright zinc-plated (BZP) finish: dependable general-purpose corrosion resistance.
• Coarse wood-screw thread: bites directly into timber for strong pull-out resistance, with no nut required on the reverse face.
• No-nut fixing method: works into a single thickness of timber, or, with a wall plug, into brick, block or concrete, ideal where the reverse face isn't accessible.
• Wide length range: stocked from M10 x 60mm up to M10 x 300mm across 11 lengths, covering everything from lighter structural fixings to deep sleeper and post connections.
• Consistent thread proportions: minimum thread length is fixed at 60% of the overall shank length under DIN 571, so longer screws carry proportionately more thread engagement.

Specification

Thread, head and drive dimensions above are as specified in DIN 571 for the M10 (10mm) thread size and are constant across every stocked length.

Typical Applications

The combination of a heavy-duty hex head, deep wood-screw thread and wide length range makes these M10 coach screws suited to a broad range of heavy-timber and masonry fixing jobs, including:

• Decking and veranda subframes: fixing bearers, joists and ledger boards where a strong, spanner-tightened connection is needed.
• Railway sleeper landscaping: securing sleepers used for retaining walls, raised beds, steps and garden edging.
• Heavy timber framing and structural joinery: connections calling for more installation torque than a screwdriver-driven fastener can deliver.
• Furniture, interior fittings and renovation: furniture making, interior fittings, and repair and renovation projects in timber.
• Fence posts, rails and gate hardware: fixing gate hinges, latches and rail brackets to substantial timber posts.
• Pergolas, carports and garden structures: joining structural timber members that need a dependable, load-bearing fixing.
• Fixing wall plates and heavy-duty ironmongery to masonry: using a suitable wall plug, the same hex-head screw drives into brick, block or concrete.
• Longer lengths (220mm–300mm): suited to deep connections through thick timber sections, or where the fixing needs to reach well into a solid masonry or sleeper substrate.

Installation Guidance

Pre-drilling is strongly recommended to prevent the timber from splitting and to ease driving:

• Drill a clearance hole through the first (fixing) timber, sized to the screw's shank, so the two timbers draw together as the screw is tightened rather than binding in the top piece.
• Drill a pilot hole into the second timber, sized to roughly the thread's root diameter (softer timbers need a smaller pilot than dense hardwoods), drilled to at least the full length of the screw.
• Drive home with a 17mm (0.67in) spanner or socket rather than a screwdriver, keeping the tool square on the head to avoid rounding off the flats.
• Fit a washer under the head as good practice; it spreads the load over a wider area and stops the head sinking into softer timber as it's tightened.
• For masonry fixings, drill to accommodate a suitable wall plug, insert the plug, then drive the coach screw in as normal.

Common Questions

Which length do I need?
Choose a length that passes through the timber you are fixing and leaves the threaded part in the timber beneath. Thread length is 60% of the screw length, listed for every size in the table above.

What spanner or socket fits?
A 17mm (0.67in) spanner or socket on every length.

Do I need to pre-drill?
Yes, pre-drilling is strongly recommended to prevent splitting: a clearance hole through the first timber and a pilot hole into the second, as in the Installation Guidance above.

Can I fix them into brick or concrete?
Yes, with a suitable wall plug in brick, block or concrete.