Carriage Bolt

  • Square Neck Bolts
  • Flat / Round Head Carriage Bolts
  • Shaker Screen Bolts
  • Carbon Steel / Stainless Steel / Alloy Steel Carriage Bolts

Category

Carriage bolts, also known as square neck bolts, feature a smooth, domed head and a square or ribbed neck directly beneath it. This square section locks into the mating material (typically wood or a pre-punched square hole in metal), preventing the bolt from rotating during nut tightening or removal. This allows for one-side installation—ideal when access to the bolt head is limited.

Shaker Screen Bolts – Heavy-Duty Carriage Bolt Variant

Shaker screen bolts are a specialized, high-strength version of carriage bolts, commonly used in vibrating equipment and screening applications. They share the same square neck anti-rotation design but are typically fully threaded and manufactured to higher strength grades (e.g., Grade 5, Grade 8) to withstand dynamic loads and vibration.

Available Head Styles

  • Round Head: The most popular style, providing a finished appearance and smooth surface

  • Flat Head: Low-profile design for applications where flush mounting is required, such as signs and garage doors

Applicable Standards

  • ASME B18.5 (Inch series carriage bolts)

  • DIN 603 (Metric carriage bolts – mushroom head square neck)

  • ISO 8677 (Metric round head square neck bolts)

Materials

  • Low Carbon Steel: For general-purpose applications (flat head carriage bolts)

  • Stainless Steel:

    • Grade 304 (A2): Excellent corrosion resistance for general outdoor use

    • Grade 316 (A4): Superior resistance to pitting and chemicals, ideal for marine environments

  • Alloy Steel: For high-strength applications (Shaker screen bolts, Grade 5/8)

Surface Treatments

  • Zinc plating (clear or yellow)

  • Hot-dip galvanizing

  • Black oxide

  • Plain finish

  • Passivation (stainless steel)

Common Applications

  • Wood-to-wood and wood-to-metal connections

  • Decking, fencing, and timber structures

  • Playground equipment and outdoor furniture

  • Signage and garage door hardware

  • Shaker screens and vibrating equipment

  • Marine and coastal construction (stainless steel)