Screw SPAX 20 mm, metal wood screw, 4 mm thread diameter, pack of 1000

SPAX screw 20 mm is a metal wood screw with a 4 mm thread diameter and a 16 mm thread length designed for reliable fastening of wooden elements. The screw features a MULTI head that allows flush countersinking in wood and positive contact on metal, ground serrations for fast engagement, and the 4CUT point which reduces splitting and often removes the need for pre-drilling depending on the wood species. The WIROX A9J surface provides enhanced corrosion protection without chromium-VI and is suitable for many interior woodworking and assembly tasks. This pack contains 1000 screws with standardized geometry for repetitive installations.

Advantages

The MULTI head combined with a cross recess Z permits secure driving and controlled countersinking. Ground serrations and the 4CUT point reduce driving torque and improve pull-in, enabling more screwed connections per battery charge when using power drivers. The WIROX A9J finish offers high corrosion resistance while being chromium-VI free, and the partial thread design provides strong clamping force for wooden joints. Together these features make the screw time-efficient for series work and reduce the risk of splitting near edges.

Suitable for

• General woodworking and interior joinery
• Assembly of wooden components and fittings
• Applications requiring reduced pre-drilling or edge-sensitive fixing
• Repetitive installation tasks and production environments

Key specifications

• Length: 20 mm
• Thread diameter: 4 mm
• Thread length: 16 mm
• Head type: MULTI head with cross recess Z
• Point type: 4CUT point for reduced splitting and often no pre-drill
• Serrations: Ground serrations for faster engagement
• Finish: WIROX A9J (chromium-VI free, enhanced corrosion protection)
• Material: Metal
• Threading: Partial thread
• Colour: Grey
• Pack quantity: 1000 pieces

How to use

Select an appropriate driver bit for the cross recess Z and the MULTI head to ensure stable engagement. For most softwoods and many hardwoods the 4CUT point can eliminate the need for pre-drilling; for very hard or brittle timbers, a pilot hole is recommended. Position the screw and drive at steady speed, allowing the ground serrations to cut cleanly. Use appropriate clutch settings on power tools to avoid overdriving when approaching final countersink depth.

Usage recommendations

For best results, test on a scrap piece of the same wood to confirm whether pre-drilling is necessary. Use a matched driver bit and moderate torque to avoid stripping the cross recess Z. Store screws in a dry environment to preserve the WIROX finish and handle interior applications where enhanced corrosion protection is required.