Traditional heavy-duty woodscrew is used mainly for timber-to-timber applications, attaching ironmongery to timber or for use with a nylon plug into masonry.
A Coach Screw is a heavy-duty screw that has a square or hexagonal head and an externally threaded cylindrical shaft that tapers to a point at the tip. They are primarily used for holding together heavy timber, fixing metal to timber and in some cases masonry or concrete.
Coach Screws are used for connecting metal to timber, or to join heavy timbers. These Coach Screws were designed for use with square plate washers on either side of a wooden beam. They are often used now however with bare timber as the Coach Screw has developed.
To avoid splitting timbers, drill a pilot hole before inserting any screw. Pilot holes should be half the diameter of the screw when using softwoods, and three-quarters its diameter when working with hardwoods. So, if you’re working with pine and you’re using a 12mm (M12) screw, drill a 6mm pilot hole. For the same screw-in mahogany, make the pilot hole 8mm. To avoid overdriving the screw when working with timber, use a washer. Drive the screws into place using the correct size spanner or socket. In applications where the finish is important, take care not to scratch the surface of the screw.
