Industrial Fastener · Bolts Series
Carriage Bolt
A carriage bolt has a smooth, domed round head with a square section under the head that bites into wood or a square hole in metal, preventing the bolt from rotating during tightening. This makes it ideal for connections that can only be tightened from the nut side.
Product Overview
Carriage Bolt sourcing essentials
A carriage bolt has a smooth, domed round head with a square section under the head that bites into wood or a square hole in metal, preventing the bolt from rotating during tightening. This makes it ideal for connections that can only be tightened from the nut side.
DIN 603, ISO 8677, ANSI B18.5
Carbon steel, Stainless 304/316
Timber joinery, wood-to-metal, fence and deck construction, agricultural equipment
Inspection records, lot labels, certificate options, and destination-ready packing.
Technical Data
Specification range
Final dimensions, mechanical properties, finish, and packing are confirmed against the RFQ and applicable standard.
| Standards | DIN 603, ISO 8677, ANSI B18.5 |
|---|---|
| Property Class | 4.6, 4.8, 8.8 (limited) |
| Diameter Range | M5 – M20 (1/4" – 3/4") |
| Material | Carbon steel, Stainless 304/316 |
| Surface Finish | Plain, Zinc plated, HDG, Black, Stainless |
| Common Use | Timber joinery, wood-to-metal, fence and deck construction, agricultural equipment |
Common surface finishes
Select an option to review its sourcing note. Exact coating system, thickness, and corrosion requirement are confirmed with the order.
Quality Control
Checked before consolidation and export
Each order is matched to the specified standard and verified at practical control points before shipment.
RFQ confirmation
Standard, size, grade, pitch, finish, certificates, packing, and destination are locked before production.
Lot verification
Critical dimensions, thread fit, markings, finish appearance, and packing labels are sampled and recorded.
Shipment approval
Photos and required reports are organized before consolidated loading and export documentation.
Buyer Questions
Frequently asked questions
How does the square neck of a carriage bolt work?
The short square section directly beneath the round head pulls into the wood (or seats into a square hole) when the nut is tightened. This grip prevents the bolt from rotating, which means you can tighten the nut without holding the head with a wrench.
Can carriage bolts be used in metal?
Yes, but the metal needs a square hole that matches the neck dimension, or the assembly must rely on friction in a round hole. Most metal-to-metal carriage bolt applications use a stamped square hole in one of the parts.
Ready to quote Carriage Bolt?
Send the standard, size, grade, finish, quantity, packing requirement, and destination. Availability and lead time are confirmed with the inquiry.