Coach Screws

When you need to make a heavy-duty timber-to-timber or timber-to-masonry connection that will carry significant load, a coach screw is the fastener to reach for. At the DIY Hardware Store, our coach screws range covers the large hex-headed timber screws used in structural joinery, garden building, gate hardware, post mounting, and any application where standard woodscrews simply aren't large enough for the job.

Coach screws (also called lag screws or lag bolts) have a coarse, deep thread that bites aggressively into timber, and a large hex head that's driven with a spanner or socket rather than a screwdriver. The combination of large shank diameter, deep thread, and high driving torque creates a joint that resists both withdrawal and shear loads in a way that no screw-drive fastener can match at equivalent size.

They're used for bolting gate posts to concrete, fixing newel posts to floors, connecting structural timber in outbuildings, and anywhere that structural integrity and load capacity matter more than the speed of installation. Pre-drilling with a pilot hole is essential to avoid splitting timber.

  • Large hex-headed timber screws for structural connections
  • Driven with spanner or socket wrench
  • Suitable for gate posts, newel posts, and timber framing
  • High withdrawal and shear resistance
  • Pre-drilling required - pilot and clearance holes
  • Zinc-plated and galvanised finishes for internal and external use