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Vagnsbultsmuttrar i varmförzinkat stål med fyrkantsfäste för säker och hållbar infästning i trä och utomhuskonstruktioner.
Vagnsbultsmuttrar i varmförzinkat stål med fyrkantsfäste för säker och hållbar infästning i trä och utomhuskonstruktioner.
Vagnsbultsmuttrar i varmförzinkat stål med fyrkantsfäste för säker och hållbar infästning i trä och utomhuskonstruktioner.
Vagnsbultsmuttrar i varmförzinkat stål med fyrkantsfäste för säker och hållbar infästning i trä och utomhuskonstruktioner.

Carriage bolt head | Hot-dip galvanized

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SKU: 101573
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Description

Coach bolts in FZV (hot-dip galvanized steel) offer good corrosion resistance for outdoor use and structures in harsher environments. The bolt features a round head with a square shoulder underneath that locks against the material during assembly.

APPLICATION AREA

Suitable for use in wood and steel structures, especially outdoors. The square neck under the head prevents rotation during assembly, which simplifies installation from just one side. The hot-dip galvanization provides long-term rust protection.

TECHNICAL SPECIFICATIONS

  • Product type: Coach bolt
  • Standard: metric
  • Quality: FZV
  • Material class: FZV
  • Thread type: metric
  • Surface treatment: hot-dip galvanized
  • Head shape: coach bolt

FREQUENTLY ASKED QUESTIONS (FAQ)

How does a coach bolt (DIN 603) work and what does the square shoulder under the head do?

DIN 603 specifies the standard for coach bolts (also known as carriage bolts):

  • Self-locking function: The square neck directly under the domed head is pressed or tapped into the wood material (or into a pre-punched square hole in steel) during assembly. This prevents the bolt from rotating when the nut is tightened from the back.

  • Smooth and safe surface: The smooth, round head lacks driver slots. This provides a clean finish without sharp edges and makes it impossible to dismantle the bolt from the outside/head side, which offers excellent theft and break-in protection.

  • One-sided assembly: Allows one person to easily assemble and tighten the connection alone using a ratchet or spanner on the nut side.

What does FZV (Hot-Dip Galvanized / HDG) mean and why is it ideal for outdoor use?

FZV (Hot-Dip Galvanized) is one of the most durable surface treatments for carbon steel in outdoor environments:

  • Thick and integrated protective layer: The bolt is dipped in molten zinc (450 °C), which creates a significantly thicker zinc layer (often 45–85 µm) compared to standard electro-galvanization (FZB, approx. 5–12 µm).

  • Cathodic protection: If the zinc layer gets a scratch, the zinc sacrificially protects the underlying steel chemically, preventing rust from spreading under the surface layer.

  • Long service life in wood structures: Perfectly adapted for heavy outdoor structures such as decks, beams, fences, piers, posts, and load-bearing timber constructions where the bolt is exposed to rain, snow, and ground moisture.

What should be considered regarding the choice of nut and washer and thread fit for FZV?

  1. Use FZV nuts and washers: Hot-dip galvanized screws have a thicker surface layer, meaning standard nuts (e.g., electro-galvanized FZB or stainless steel A2/A4) may bind or be impossible to screw on at all. Always use FZV nuts (e.g., Hexagon nut DIN 934 FZV) and FZV washers (DIN 125 FZV / DIN 440 for wood) that are threaded with the correct tolerance for hot-dip galvanization.

  2. Pre-drilling in wood: Always pre-drill the hole in the wood material with the same diameter as the bolt's nominal thread. The square neck is then automatically pulled into the wood when the nut is tightened from the back.