Coach Screws: Your Complete Guide
What is a coach screw?
Coach screws are heavy duty screws primarily used to fix timber to timber. You can also use them to fix ironmongery or concrete to timber.
Coach screws have a hexagonal head with a threaded barrel tapered to a pointed tip. This head shape allows you to apply more torque with a spanner or wrench when fixing.
Coach screws are also known as lag screws or lag bolts but be careful not to confuse them with coach bolts or carriage bolts as they are very different.
The difference between coach screws and woodscrews
Coach screws differ to woodscrews due to their size. Woodscrews range between 3mm and 6mm in thickness. Coach screws range from 6mm to 12mm in thickness, making them a much heavier duty fixing.
Do I need a washer with a coach screw?
Coach screws are classed as ‘single-component’ fixings so no, you don’t need a washer. That said, you can use a washer to give a flat surface for the bolt to fix against. Using a washer will also reduce the chance of the timber splitting as you tighten the screw.
How to use a coach screw
When fixing to timber you need to drill a pilot hole first to prevent the wood from splitting. You can then drive the screw directly into the material. We do advise using a washer not only to protect the timber but also to make it easier to remove the coach screw in future if you need to.
When fixing to heavy duty materials, such as concrete or brickwork, you need to drill a hole and use a wall plug. The wall plug needs to be the same size as the hole you’ve drilled, both in depth and diameter. This is a must-do to keep everything securely in place.
It’s also important to make sure you’ve got an appropriately sized spanner or wrench for the job to avoid damaging the screw head.
What are coach screws made of?
Coach screws are generally made using mild steel. This allows them to adapt to any changes or flexes in the material that can occur over time.
When fixing to certain types of wood, such as oak, it’s better to use stainless steel coach screws as the acid in this variety of timber can corrode carbon steel coach screws.
Shop our range of coach screws
At Fastco we stock a wide range of coach screws to cover the requirements of any project.
Explore our range of coach screws.
Free delivery is available on orders over £30.
You can order direct from the website, email sales@fastco.co.uk or call us on 01270 252326 to place your order.