Coach bolts vs coach screws

A question that often arises when speaking about coach bolts is: are coach bolts the same as coach screws? Short answer, no. Coach bolts are not the same as coach screws. These are different types of fixings designed for different purposes. So, what are the differences?

Coach bolts.

Also known as carriage bolts and cup square hex bolts, coach bolts feature a very unique design. These bolts have a round mushroom head and a square underside that prevents coach bolts from moving or turning when being installed.

These bolts are commonly used in the timber and construction industries when fastening timber to timber. More specialised coach bolts can also be used to fasten metal to wood or even metal to metal. Coach bolts will require a nut and washer to be securely fastened to the surface. Plus, due to the non-tapered nature of bolts, coach bolts will always require an adequately sized pilot hole.

coach bolts

Coach bolts are available in various finishes and materials, such as galvanised coach bolts, stainless steel coach bolts and zinc plated coach bolts. These also come in a variety of thread sizes and lengths, from M12 stainless steel coach bolts to M8 zinc plated coach bolts with nuts.

Coach screws.

These screws, also called lag screws, are heavy-duty screws suitable for timber to timber supports, gate construction and fence construction. These feature a hexagon head and a tapered shaft. As these feature a tapered shaft, coach screws can be fastened straight into wood or masonry.

However, it is recommended to screw these into a pilot hole to prevent wood from splitting. When fixing coach screws to wood, use a washer to avoid countersinking the screw head. Use plastic plugs when fixing coach screws to masonry.

coach screws

Coach screws can be purchased in an array of materials, sizes and finishes. Some of the coach screws available online include galvanised coach screws, zinc plated coachscrews and stainless steel coach screws.