Coach Bolts for Fencing, Gates and Timber Frames

Coach bolts are widely used across fencing, gate installation and timber frame construction. Their square neck and domed head provide a secure fixing with a clean finish on exposed surfaces.

This guide covers how coach bolts are used in practice, which sizes are typically selected, and how to choose the right material for the job.

Why coach bolts are used for timber fixing

Coach bolts are designed for through-fixing. The square section under the head locks into the timber, preventing rotation while tightening the nut.

Secure clamped fixing through timber
Neat domed head on the visible side
Suitable for structural connections
Reliable for long-term installations

Coach bolts for fencing

In fencing applications, coach bolts are commonly used to fix rails to posts and secure timber components.

Post and rail fencing
Fence panels and supports
Timber brackets and fixings

M8 and M10 coach bolts are typically used for standard fencing work, depending on timber size and load.

Coach bolts for gates

Gates place higher loads on fixings due to movement and weight. Coach bolts are commonly used to secure hinges, braces and frame connections.

Hinge fixing to posts
Gate frame assembly
Bracing connections

M10 and M12 coach bolts are commonly used for gate installations where additional strength is required.

Coach bolts for timber frames

In timber frame construction, coach bolts are used for structural connections between larger timber sections.

Beam-to-post connections
Timber frame joints
Load-bearing assemblies

M12 and above are typically used depending on load and design requirements.

Typical coach bolt sizes for applications

Application	Typical Size
Fencing	M8 – M10
Gates	M10 – M12
Timber frames	M12 and above

Choosing the right length

The bolt should pass through all materials and allow enough thread for a washer and nut.

Measure total material thickness
Allow space for washer and nut
Avoid excessive thread overhang

Material selection for outdoor use

Material choice is important for fencing and external timber work.

Zinc plated – suitable for internal or low exposure use
A2 stainless steel – suitable for general outdoor applications
A4 stainless steel – recommended for coastal or high exposure environments

For more detail, see our A2 vs A4 stainless steel guide.

Coach bolts vs coach screws for these applications

Coach bolts are used where a through-fixing is possible and maximum strength is required.

Coach screws are often used where access is only available from one side.

See our coach bolts vs coach screws guide for a full comparison.

Available coach bolt ranges

Important: Whilst zinc plated coach bolts generally come supplied with nuts, stainless steel coach bolts do not. Be sure to add stainless steel nuts to your order if you need them.