Round head, square neck locks in fittings
The rounded head sits smooth on the outside face, and the square neck seats in the fitting's square hole so the bolt cannot spin as the nut goes on.
Bolts & Fittings
Carriage Bolt
Carriage Bolt is a round-headed bolt with a square neck under the head that locks into the square holes of fence fittings, so the bolt cannot turn while the nut is tightened. In fencing it fixes tension bands, brace bands and rail ends to chain-link posts, and pales to palisade rails. It is a coach bolt or cup square bolt in the UK and a cup head bolt in Australia. Specify the diameter, length, finish and the quantity you need.
At a glance
Carriage Bolt at a glance.
5/16 and 3/8 in for fence fittings
1/4 to 1/2 in (M6 to M12), 1-1/4 to 12 in (25 to 300 mm) long, UNC or metric coarse thread, Grade 2 or Grade 5 (Class 4.6 or 8.8), hot dip galvanized.
Attaches tension and bracing components
Fixes tension bands and brace bands to terminal posts, rail ends to posts, and palisade pales to their rails.
Also known as
Carriage Bolts are coach bolts or cup square bolts in the UK and cup head bolts in Australia; in other languages they are boulon TRCC (French), Schlossschraube (German) and bullone testa tonda (Italian).
- UK & Ireland
- Australia & NZ
- Français
- Deutsch
- Italiano
Square neck locks the bolt in place
Push the carriage bolt through the fitting hole; the square neck seats and prevents rotation. Thread the nut onto the exposed end and tighten. The bolt remains fixed while the nut draws components together under tension, securing bands and fittings against movement.
Choosing between
Carriage bolt or machine bolt.
Both hold fencing steel together. The head decides which one suits the joint.
Common applications
Where it is used.
Tension band fastening in chain-link fence
Clamp tension bands and the tension bar to terminal posts so the edge of the mesh stays fixed.
Palisade pale attachment to rails
Secure vertical pales to horizontal angle rails in BS 1722-12 palisade systems with M8 pale bolts and shear nuts.
Brace band and rail-end hardware
Fix brace bands and rail ends to posts, where the smooth head faces out and the square neck stops the bolt turning.
Questions answered
Common questions.
What is a carriage bolt called in different regions?
Carriage Bolt is a carriage bolt in the US, a coach bolt or cup square bolt in the UK and Ireland, a cup head bolt or coach bolt in Australia, a boulon TRCC in French, a Schlossschraube (DIN 603) in German and a bullone testa tonda con quadro sottotesta in Italian.
What size carriage bolts are used for tension bands and fence fittings?
Carriage Bolt for chain-link fittings is usually 5/16 or 3/8 inch, the sizes that fix tension bands and brace bands to terminal posts. Corona makes it from 1/4 to 1/2 inch (M6 to M12) and 1-1/4 to 12 inches long, in Grade 2 or Grade 5, hot dip galvanized.
In chain-link, palisade and gate hardware
Carriage Bolt fixes the bands and fittings of the chain-link fence framework, the pales of palisade fencing, and gate hardware.
Explore fencing systemsCarriage Bolt specifications
Carriage Bolt configuration
ParameterUS / PrimaryMetric / Additional
Size1/4-1/2 in (5/16 and 3/8 in for fence fittings)M6-M12
Length1-1/4-12 in25-300 mm
HeadRound head, square neckMushroom head, square neck
ThreadUNC coarseMetric coarse
GradeGrade 2, Grade 5Class 4.6, 8.8
FinishHot Dip GalvanisedHot Dip Galvanised
Fencing Systems
Related components
Palisade Fence
Palisade Fence
Pale profile: D section or W section; triple pointed, single point, round top, notched round top or flat top · Pale thickness: 2.0, 2.5, 3.0 mm; up to 4.0 mm
Specifications
Fencing Components
Barbed Wire Arm
Size: 14 G x 1-5/8, 1-7/8, 2, 2-3/8, 2-1/2 in post / — · Type: 3-strand 45° arm, 3-strand vertical arm, 6-strand V arm
Specifications
Fencing Components
Tension Bar
Size: 3/16 x 5/8, 3/16 x 3/4, 1/4 x 3/4 in / 20 x 5, 25 x 5 mm · Length: For 3-12 ft fences; 2 in shorter than the fabric / 0.9-3.6 m; 50 mm shorter than the fabric
Specifications