DIN 603 Carriage Bolt Specifications
DIN 603 Carriage Bolts
ISO Equivalent: ISO 8677 | Round Head Square Neck Bolts
DIN 603 defines carriage bolts — fasteners with a smooth, domed head and square neck that prevents rotation during tightening. Designed for through-hole applications in wood, metal, and composite materials.
Quick Specifications
Key Features
Anti-Rotation Square Neck
Square section under the head digs into wood or seats in square holes to prevent spinning during nut tightening.
Smooth Domed Head
No drive recess means tamper resistance and a clean, finished appearance on the visible side.
Wood-Friendly Design
The domed head won't snag clothing or cause injury — ideal for playground equipment, furniture, and decking.
One-Sided Access
Only need wrench access from the nut side — no need to hold the head while tightening.
Dimension Chart
| Size | Pitch | Head Dia. (dk) | Head Height (k) | Square Width (c) |
|---|---|---|---|---|
| M5 | 0.8 mm | 11.0 mm | 3.5 mm | 5.0 mm |
| M6 | 1.0 mm | 13.5 mm | 4.0 mm | 6.0 mm |
| M8 | 1.25 mm | 17.5 mm | 5.0 mm | 8.0 mm |
| M10 | 1.5 mm | 22.0 mm | 6.0 mm | 10.0 mm |
| M12 | 1.75 mm | 26.0 mm | 7.0 mm | 12.0 mm |
| M16 | 2.0 mm | 34.0 mm | 9.0 mm | 16.0 mm |
| M20 | 2.5 mm | 42.0 mm | 11.0 mm | 20.0 mm |
Property Classes
Common Applications
DIN 603 vs ISO 8677
💡 Are They Interchangeable?
Yes — DIN 603 and ISO 8677 are dimensionally equivalent. Both standards define the same:
- Domed head diameter and height
- Square neck dimensions
- Thread specifications
- Fully interchangeable in all applications
Shop DIN 603 Carriage Bolts
Available in zinc plated, hot-dip galvanized, and stainless steel. Sizes M5 through M20.
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