Wood Screw Koelner/Rawlplug CS-8220 8x220 mm, washer head

Koelner/Rawlplug CS-8220 8x220 mm is a wood construction screw with a washer head designed for secure fastening of timber elements in construction and carpentry. With a length of 220 mm and an 8 mm shank diameter, this fastener is intended for connections that require deep penetration and high load-bearing capacity. The washer head increases bearing surface and reduces pull-through in softer wood while the coarse thread ensures efficient driving and good holding power in a variety of wood types.

Advantages

The washer head design distributes pressure over a larger area, lowering the risk of surface damage and improving joint stability. The long 220 mm length allows for through-fixing of beams and multilayer timber assemblies without the need for additional connectors. Coarse threading and a robust shank provide strong withdrawal resistance and reduce splitting when pre-drilling is used appropriately. The screw is suitable for structural and non-structural wooden connections, offering predictable performance in common carpentry tasks.

Suitable for

• Joining beams and posts in timber framing
• Securing decking boards and substructures
• Fixing wooden bearers and sill plates
• Fastening multilayer or laminated timber elements
• General carpentry and construction woodwork requiring long fasteners

Key specifications

• Diameter: 8 mm
• Length: 220 mm
• Head type: washer head for increased bearing area
• Thread type: coarse wood thread for efficient grip in timber
• Intended material: solid wood, engineered wood, and laminated timber

How to use

Select the appropriate pilot hole diameter based on wood species and density to reduce splitting and improve driving. For dense hardwoods, pre-drilling is recommended along the full length of the screw; for softwoods a shorter pilot hole may suffice. Use an appropriate driver bit and a drill or impact driver set to a controlled speed and torque to drive the screw until the washer head sits flush against the surface. Ensure alignment of connected elements and verify adequate embedment to achieve designed load-bearing performance.

Usage recommendations

For structural connections, follow local building codes and engineering specifications regarding fastener spacing, edge distances, and load requirements. Where exposure to moisture or outdoor conditions is expected, use compatible corrosion-resistant fasteners or protective coatings to maintain long-term performance.