Wood construction screw Koelner/Rawlplug 8x400 mm washer head CS-8400

Wood construction screw Koelner/Rawlplug 8x400 mm washer head CS-8400 is a heavy-duty fastener designed for structural timber connections. The 8x400 mm dimension provides deep penetration for secure joints in solid wood, laminated beams and heavy carpentry. The large washer head increases bearing area to reduce local compression and pull-through, making it suitable for load-bearing assemblies used indoors and in protected outdoor locations.

Advantages

The washer head design distributes load over a larger surface, decreasing the risk of wood crushing and improving joint stability. The length and diameter ensure strong withdrawal and shear capacity for structural timber elements. These screws are intended for quick, reliable installation with appropriate pre-drilling and are compatible with common construction tools and bit drives. Their characteristics support durable connections in beams, posts and heavy timber frameworks.

Suitable for

• Structural timber connections in residential and light commercial construction
• Joining solid wood, glued laminated timber (glulam) and large cross-section carpentry elements
• Beam-to-beam, beam-to-post and ledger attachments where high bearing area is required
• Indoor and protected outdoor timber assemblies where moisture exposure is limited

Key specifications

• Diameter: 8 mm
• Length: 400 mm
• Head type: large washer head for increased bearing area
• Intended materials: solid timber, laminated beams, heavy carpentry wood
• Application: structural connections with high withdrawal and shear requirements

How to use

For reliable performance, mark and align the components, then pre-drill a pilot hole sized appropriately for the 8 mm shank and the timber species to prevent splitting. Position the screw and drive it using a suitable impact driver or drill with the correct bit until the washer head bears evenly against the wood surface. For load-bearing connections ensure correct embedment depth and follow applicable structural fastening standards. Use appropriate corrosion-resistant screws or protective measures if exposure to moisture or corrosive environments is expected.

Usage recommendations

When installing in glued laminated timber or large cross-sections, verify spacing, edge distances and embedment per design specifications. Always use pilot holes and the recommended driving tools to maintain structural integrity and consistent performance of the connection.