COACH BOLTS/SCREWS

Coach bolts and coach screws are often confused with each other, the main difference is in their installation and design.

A coach bolt (sometimes called cup square hex or carriage bolt) has a smooth shank and requires a nut and pre-drilled hole, while a coach screw has a coarse, self-tapping thread and a square or hex head for screwing directly into timber.

Summary Comparison

Feature 

Coach Bolt (Carriage Bolt)

Coach Screw

Head Type

Domed, tool-less head with a square under section

Hexagon head

Thread Type

Machine thread, requires a nut

Coarse, self-tapping wood thread

Installation

Requires access to both sides for bolt and nut

Installed from one side with a spanner/socket

Strength

Superior holding strength, resists movement well

Very strong, but may loosen slightly as timber moves

Application

Structural connections, metal to wood, high security areas

Heavy timber construction, decking, fencing
COACH BOLTS/SCREWS
COACH BOLTS

COACH BOLTS
COACH SCREWS

COACH SCREWS