304 (A2) · 316 (A4) · Class 10.9 · Class 4.6 · Class 8.8 · Grade 8 · Mild Steel
Coach Bolts (Cup Head Bolts)
Cup head bolts (coach bolts) with a domed head and square neck for bolting through timber posts, beams and gates, and for farm machinery.
About the Coach Bolts (Cup Head Bolts)
Cup head bolts, also called coach bolts or carriage bolts, have a smooth domed head and a square neck that bites into timber so the bolt cannot turn while you tighten the nut: they bolt through posts, beams, gates, playground timber and farm machinery. They come galvanised or zinc plated (class 4.6, 8.8 and 10.9 to AS 1390), or in 304 and 316 stainless steel, from M6 to M24 and in imperial sizes, as bolt and nut kits or bolts only. Choose the finish, size and length above; the guide below covers grades and fitting.
Also called coach bolts or carriage bolts.
Features
- Round cup head with square neck
- Supplied as a bolt and nut kit
- Made to AS1390
- Available in class 4.6, 8.8 and 10.9
- Hot dip galvanised for corrosion resistance
Applications
- Bolting through timber posts, beams and bearers
- Gates, fences and playground timber
- Seeders, scarifiers, harvesters and cultivators
What coach bolts are for
A cup head bolt, usually called a coach bolt or carriage bolt, has a smooth domed head with a square neck underneath. The square neck pulls into the timber as the nut is tightened, so the bolt cannot turn and there is nothing to grip on the head side: neat, and harder to undo from outside.
They are the standard bolt for through-bolting timber in decks, pergolas, fences, posts and beams, and the high tensile class 8.8 bolt and nut kits are made for agricultural machinery such as seeders, scarifiers, harvesters and cultivators.
Grades and finishes
- Class 4.6 (AS 1390): the general purpose coach bolt for timber construction.
- Class 8.8 and 10.9 (AS 1390): high tensile, for farm machinery and heavier connections.
- Hot dip galvanised: outdoor timber construction, fencing and farm. Zinc plated: indoor and dry use.
- 304 and 316 stainless (DIN 603 and ANSI B18.5): wet, coastal and on-show work; 316 near the sea.
- Supplied as a bolt and nut kit or as bolts only, part or fully threaded, metric M6 to M24 and imperial 1/4 to 1/2 inch.
How to fit a coach bolt
- Drill straight through both pieces at the bolt diameter, so the square neck has timber to bite into.
- Tap the bolt through until the head sits on the timber.
- Fit a large washer and the nut on the far side.
- Tighten the nut: the square neck pulls into the timber and stops the bolt turning.
- Check and retighten after the timber has dried and shrunk.
Coach bolts in Adelaide
Allmat supplies coach bolts, coach screws, washers and timber connectors, with the timber, to builders, fencers and farmers across Adelaide and South Australia. Add them to a quote with the rest of your list, and we will price the lot.
Coach bolts for decks, pergolas, fencing and farm
Galvanised, zinc and stainless coach bolts, with washers, nuts and brackets, are available to order from Allmat for builders, carpenters, fencers, farmers and trade across Adelaide and South Australia, with the timber to go with them. Order through Allmat, we pick and pack it, then click and collect from the Allmat yard or have it delivered to site.
Goes with
Questions
Is a coach bolt the same as a cup head bolt?
Yes. Coach bolt, cup head bolt and carriage bolt all describe a domed head bolt with a square neck.
What size hole for a coach bolt?
Drill at the bolt diameter, for example 12mm for an M12 coach bolt, so the square neck bites into the timber.
Coach bolt or coach screw?
A coach bolt goes right through both pieces with a nut on the far side. A coach screw has a hex head and screws into the timber where you cannot get to the back.
Galvanised or stainless coach bolts?
Galvanised for most outdoor timber, fencing and farm work. 316 stainless for coastal, marine and on-show work.
Do your coach bolts come with nuts?
Most are bolt and nut kits; some are bolts only. The selector shows which.
Where can I buy coach bolts in Adelaide?
Order through Allmat. Order ahead by phone on 1300 03 03 63 or send your list for a quote, then click and collect from 25 Kapara Road, Gillman, or have them delivered to site.
Coach Bolts (Cup Head Bolts): sizes and finishes we supply
458 lines by type and finish. Pick one above for its product code and pack sizes.
| Type | Finish | Sizes | Lengths | Lines |
|---|---|---|---|---|
| Cup / dome head | Galvanised | M6, M8, M10, M12, M16, M20, M24 | 20 to 600 (41 lengths) | 209 |
| Cup / dome head | Zinc Plated | 1/4, 5/16, 3/8, 7/16, 1/2 | 3/4 to 18 inch (22 lengths) | 72 |
| Cup / dome head | Zinc Plated | M6, M8, M10, M12 | 18 to 200 (24 lengths) | 70 |
| Cup / dome head | 316 Stainless | M6, M8, M10, M12, M16 | 20 to 350 (17 lengths) | 44 |
| Cup / dome head | 304 Stainless | 1/4, 5/16, 3/8, 1/2 | 3/4 to 6 inch (11 lengths) | 35 |
| Cup / dome head | Steel | M12, M16, M20 | 50 to 400 (20 lengths) | 27 |
| Cup / dome head | 304 Stainless | M10 | 20 | 1 |
Data sheets and documents
The documents for the product you choose are listed with the selector above. Here is every Coach Bolts (Cup Head Bolts) document from Hobson Engineering.
All Coach Bolts (Cup Head Bolts) documents (12)
Data sheets and technical data (4)
Did You Know flyers (2)
Need them in bulk?
Add the sizes you need to your quote, or send us your list and we’ll price the lot and supply it with the rest of your order.
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