Carriage bolts have a smooth domed head with a square neck underneath. The square neck locks into the timber so the bolt does not turn while the nut is tightened, and the round head leaves no edge to catch on. In Australia and New Zealand they are usually called cup head bolts, and sometimes coach bolts.
Linkworld supplies carriage bolts in carbon steel and stainless steel, with plain, zinc plated or hot-dip galvanised finishes, for timber merchants, hardware distributors and builders’ suppliers. They can be made to DIN 603 or your drawing, supplied with nuts and washers, and packed in bulk cartons or your own branded packs.
Carriage Bolt Specifications
| Specification | Configuration |
|---|---|
| Product | Carriage bolt / cup head bolt / coach bolt |
| Thread sizes | M6, M8, M10, M12, M16 and M20 |
| Common lengths | 30 to 300 mm |
| Material | Carbon steel class 4.6; stainless steel 304 or 316 |
| Finish | Plain, zinc plated or hot-dip galvanised |
| Head | Domed cup head with square neck, DIN 603 or to drawing |
| Sets | Bolt only, or with nuts and washers |
| Packing | Bulk cartons, own-brand boxes, buckets and small packs |
Other sizes and finishes can be made to drawing or sample.
Where Cup Head Bolts Are Used
- Decks and pergolas bearers, posts and beams
- Fences and gates rails, posts and hinges
- Playgrounds and park furniture where a smooth head is safer
- Timber framing bolted timber connections
- Trailers timber floors and sides
Choosing Carriage Bolts
- Finish: hot-dip galvanised for outdoor timber, 316 stainless for coastal and treated timber, zinc for indoor use.
- Length: cover the timber thickness, washer and nut with a few threads spare.
- Neck: drill the hole to the bolt size so the square neck grips the timber.
- Sets: order nuts and washers in the same finish as the bolt.
Common Purchasing Mistakes
Mixing galvanised bolts and zinc nuts. Use hot-dip galvanised nuts with galvanised bolts, and stainless nuts with stainless bolts.
Using zinc plated bolts outdoors. Zinc plated bolts suit indoor work only.
Ordering by the wrong name. Cup head, coach and carriage bolts are the same product. Use your customers’ name on the label.
Short bolts. Allow for the washer and nut when choosing length.
What to Send with Your Enquiry
| Item | What to tell us |
|---|---|
| Size | Diameter and length |
| Material | Carbon steel or 304 / 316 stainless |
| Finish | Plain, zinc or hot-dip galvanised |
| Sets | Bolt only, or with nuts and washers |
| Quantity | Quantity for each size |
| Packing | Bulk carton, own-brand box, bucket or small pack |
| Destination | Destination port |
Packing and Supply for Distributors
We pack cup head bolts in bulk cartons for trade distribution, or in your own branded boxes, buckets and small packs for retail. Each size can carry its own label. For customers who plan several deliveries through the year, we offer free warehouse storage and staged shipments.
Work With Linkworld
Linkworld has more than 20 years of fastener export experience and runs its own cold heading workshop. Our own QC team checks head, neck, thread and coating in our inspection room before every shipment. We make bolts to standard or drawing, so special lengths and packs are welcome.
Frequently Asked Questions
Are carriage bolts and cup head bolts the same?
Yes. Cup head bolt is the usual name in Australia and New Zealand; coach bolt is also used.
What sizes do you supply?
M6 to M20 in lengths of about 30 to 300 mm.
Which carriage bolts are best for decks?
Hot-dip galvanised bolts for general decks, and 316 stainless steel for coastal decks.
Do you supply cup head bolts with nuts and washers?
Yes. We supply them as sets in matching finishes.
Can you pack carriage bolts in our own boxes?
Yes. We pack in bulk cartons or in your own branded boxes and small packs.
Looking for cup head bolts in your own sizes or packs?
Send the sizes, finish, quantity and packing you need through the enquiry form below, and our team will reply with the options that fit your range.
Send an Enquiry
Send a drawing, sample or clear reference photo. Add the quantity and application if available, and we can start from the information you already have.