Spax T-Star Mixed Head T Stainless Steel Screw (Dia)4mm (L)40mm, Pack Of 25 - Silver

You will need a T-STAR plus T20 driver bit for these 4.0 x 40mm screws.

Yes, they are constructed from A2 grade stainless steel, which offers excellent corrosion resistance and is ideal for outdoor applications.

Pre-drilling is recommended for optimal results, especially in dense hardwoods or when screwing near the edge of a material, to prevent splitting and ensure accurate positioning. For softer woods, it may not always be necessary.

The serrations on the thread reduce the torque required to drive the screw, making installation faster and easier with less effort.

The 4CUT point provides precise screw positioning and helps to minimize material splitting during installation, leading to cleaner work.

These screws are designed for general-purpose fastening in woodworking, construction, and maintenance. For critical structural applications, consult engineering specifications and use screws specifically rated for those purposes.

A2 stainless steel (also known as 304 grade) provides good corrosion resistance, particularly against atmospheric conditions and many chemicals. It is a common choice for general-purpose, corrosion-resistant fasteners.

Ensure a pilot hole has been pre-drilled, especially in hardwood. Verify the pilot hole size is appropriate (slightly smaller than the screw core). Check that the T-STAR bit is fully engaged in the recess and that the drill/driver is set to the correct rotational direction (clockwise for driving).

Ensure you are using the correct T20 T-STAR plus bit. Apply firm downward pressure directly in line with the screw. Check if the screw head recess is damaged. If it is, replace the screw.

This can happen if the screw is over-driven or if the material is too dense without adequate pre-drilling. Reduce driving torque or ensure proper pilot hole preparation. If the head breaks, carefully remove the shank with pliers or an extractor if necessary.

Ensure the 4CUT point is properly engaged before driving. Use a pilot hole, especially when screwing close to the edge of the material. Reduce driving torque if the splitting persists.