FASTSHIFTER Screw for Aluminium Joist 4.2×38mm – 1 pcs

The FASTSHIFTER hidden fastening screw 4.2 × 38 mm is made specifically for fixing timber deck boards onto aluminium joists — a combination that ordinary wood screws handle badly. Its self-drilling tip is designed to cut through the aluminium wall, so no pre-drilling is needed.

The screw is SS410 stainless steel with a black coating, driven with a T15 bit. Supplied in packs of 1 pcs.

Key features

• Self-drilling tip engineered to penetrate aluminium joist walls.
• Special double thread for a firm board-to-joist connection.
• Designed for timber-on-aluminium substructures specifically.
• Conical head for a better visual finish.
• Drilling tip leaves fewer splinters in the board edge.
• Optimised length — 38 mm, matched to standard aluminium joist profiles.
• SS410 stainless steel, black coated for outdoor durability.

Where it is used

• Timber and WPC decking laid on aluminium joist systems.
• Hidden-fastener installations using clips on an aluminium frame.
• Roof terraces and balconies, where aluminium substructures are standard.
• Any deck where the substructure will outlive several sets of boards.

SS410 is harder than the usual A2 or A4 grades, which is what allows the tip to drill aluminium. That same hardness makes it less suitable for larch and dense hardwoods — use an A2 or A4 screw there instead.