So, for example, a screw with the dimensions M8 x 100mm is 8mm in diameter at the thread’s maximum width and 100mm in length from the screw tip to the base of the screw head. The screw head itself remains proud of the drill hole. Bright zinc plated – provides moderate corrosion resistance and is suitable for indoor use in a dry environment

When using coach screws on timber, it is advisable to add a washer to avoid embedding the screw head into the wood on impact. This will also make it easier to remove the screw at any point. Another option is a flanged coach screw. This is a coach screw with an integrated washer built into the head. Masonry It is advisable to drill a pilot hole in the timber before fixing as this will reduce the chances of splitting the timber, particularly when working close to the edge. As a rule of thumb, the pilot hole diameter needs to be half the diameter of the coach screw when using softwood and three-quarters when using hardwood. So for example, when inserting an 8mm coach screw, the pilot hole needs to be 4mm for softwood and 6mm for hardwood. Once the pilot hole has been drilled, the coach screw can be driven directly into the wood.Passivated – this is a two-part deep cleansing process to remove free iron or other contaminants from the surface. This process maximises stainless steel corrosion resistance

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. Lag screws have two measurements. The M rating is the diameter of the screw thread; the measure in mm is the length of the screw from screw tip to the underside of the hexagonal head. How do you choose the right coach screws for your application? And how do you select the right coach screw sizes? Washers can be used with the coach screws to give a flat surface for the bolt to fix against and also to reduce the chance of the timber splitting as the screws is tightened. At Fastco we have repair washers ranging in sizes between 20mm and 50mm in diameter.

Turbo TX Woodscrews

Stainless steel – offers high corrosion resistance making them ideal for outdoor use. They are also highly recommended for use with timber such as oak and cedar as these particular types of wood can contain acid and chemicals which can corrode metal. There are two main stainless steel grades: Galvanised coach screws are zinc-coated, low-cost steel screws. Typically a matt finish, these screws are often used in automotive parts, sheet metals, industrial applications and construction. The zinc coating offers corrosion resistance. This makes galvanised coach screws suitable for outdoor, hot, wet and humid environments.

Passivated (or zinc plated) coach screws are electroplated using a zinc coating. Many of our passivated products are then finished in yellow chromate. Passivation offers increased corrosion resistance, although for maximum corrosion resistance use a galvanised screw. Unlike the galvanised option, however, passivated screws typically have a high-shine finish. These are ideal for applications where aesthetics are important.Stainless steel coach screw types are great for outdoor use. Because there’s no coating, the corrosion resistance comes from the screw’s composition. Stainless steel coach screws are our most durable type and are also resistant to the oils and acids in many timbers. For certain types of wood such as oak it is better to use stainless steel coach screws as the acid in this variety of timber corrodes carbon steel coach screws. 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. Our range or coach screws varies from screw diameters, lengths, head types and finishes. Browse from our range of zinc and yellow passivated or exterior coated green finish types to find the right product for you needs.

Browse our range and you’ll typically see three types available: passivated, galvanised and stainless steel. Also known as lag screws or lag bolts, they are heavy-duty screws that are designed for metal to timber connections, or to join heavy timbers. All coach screws require a pilot hole, using a general-purpose drill bit such as a twist drill bit, before they are screwed into place, preventing wood splitting. You will need a wood drill bit to drill the pilot hole. They are slightly different from metal drill bits as they have a point at the end to stop them from slipping out of position. A4(316) - can handle high and low temperatures but has a higher corrosion resistance making them ideal for coastal areas or areas with high pollution

TurboSilver Woodscrews