M12 x 30mm Cup Square Carriage Coach Bolt A2 (304) Stainless Steel, DIN 603

Corrosion Resistant Carriage Bolt

Carriage bolt with a smooth head, no drive recess for security, and a square neck beneath the head that prevents rotation when tightened from the back.

The square neck under the rounded head locks into wood or metal. This prevents rotation during installation which allows easy one-sided fastening.

The smooth round head allows for a clean finish and with no drive recess restricts the bolt from being removed or tampered with without clear access to the back.

This adds an element of security to applications where disassembly should be restricted. A combination that sees these coach bolts widely used and being manufactured from A2 stainless steel makes them versatile for both internal and external uses.

Known in the trade as carriage bolts, coach bolts, cup square carriage bolts, and used by DIY enthusiasts and professionals alike.

M12 Carriage Bolt Specification

• Diameter (TD): M12 - 12mm
• Neck width (NW): 12.7mm max
• Neck depth (ND): 8.75mm max
• Length (L): 30mm
• Head width (HW): 30.6mm max
• Dome head height (HH): 6.95mm max
• Material: A2 stainless steel
  

FAQs about Coach Bolt (Carriage Bolt)

Where are carriage bolts commonly used?

These bolts are most commonly used to fix wood to wood or wood to metal structures such as decks, garden furniture, timber frames, fencing, and structural joinery. The square neck, below the head, locks into the material and prevents the bolt from spinning when tightened.

How does the square neck benefit installation?

The square neck under the domed head bites into timber or a square hole, providing anti-rotation while tightening the nut. This means you often don’t need a tool on the bolt head as the square neck holds the bolt in place, making assembly easier.

Can I use this bolt without a pre-drilled hole?

Manufactured with a flat end, these bolts need a predrilled hole through the material that matches the M12 diameter.

Can these Coach Bolts be used outdoors?

These Coach Bolts are manufactured in A2 stainless steel with a high level of corrosion resistance making them ideal for both internal and external applications.