Product Summary

Longo Parafusos de carruagem (also known as Coach Bolts or Cup Head Square Neck Bolts) are manufactured according to DIN 603 e ISO 8677 standards, widely used in timber construction, security fencing, play

equipment, and automotive bodybuilding. Featuring a smooth, domed head and a square neck underneath, these Longo Parafusos de carruagem are designed to lock into wood or a square hole in metal, preventing the bolt

from turning while the nut is being tightened from the opposite side.

• ✔ Anti-Tamper Design: The smooth, rounded head has no drive (like a slot or hex), making it nearly impossible to loosen from the exterior side—ideal for security applications.

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• ✔ Self-Locking Square Neck: The square shoulder under the head "bites" into timber or fits perfectly into pre-punched square metal holes, allowing for one-sided installation.

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• ✔ Extra Large Head Options: Longo provides specialized Large Head DIN 603 variants that offer a greater bearing surface, preventing the bolt from pulling through soft woods or composite materials.

Key Features of Parafusos de carruagem

• Aesthetic & Safe Finish – The low-profile mushroom head provides a clean look and reduces snagging hazards in public spaces like playgrounds or decks.

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• Superior Pull-Through Resistance – The wide head design distributes clamping force over a larger area, protecting the integrity of the wood.

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• High-Strength Materials – Available in Grade 4.8 and 8.8 Carbon Steel, as well as marine-grade Aço inoxidável.

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• Global Standard Compliance – Fully compatible with Metric (DIN/ISO) and Imperial (ASME) sizing for international export.

Technical Specifications

• Standards: DIN 603 / ISO 8677 / ASME B18.5 / BS 4933

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• Metric Size Range: M5 to M24

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• Inch Size Range: 1/4" to 1" (UNC / UNF)

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• Property Class: Grade 4.8, 8.8 / Stainless Steel A2 to A4

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• Neck Style: Square Neck (Standard) / Ribbed Neck (Custom)

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• Finish: Zinc Plated (Clear/Yellow), Hot-Dip Galvanized, Black Oxide, Plain

• Material & Mechanical Properties

• Material	Nota	Tensile Strength	Yield Strength	Aplicativo
  Carbon Steel	4.8	420 MPa	340 MPa	General Woodworking
  Carbon Steel	8.8	800 MPa	640 MPa	Structural / Machinery
  Aço inoxidável	SS304 (A2)	$\ge 700$ MPa	$\ge 450$ MPa	Outdoor Decks / Furniture
  Aço inoxidável	SS316 (A4)	$\ge 800$ MPa	$\ge 600$ MPa	Coastal / Marine Structures

• Dimensions & Global Size Conversion
• Technical Standard: Longze provides high-quality carriage bolts (Coach Bolts) manufactured to DIN 603 and ASME B18.5 standards. These bolts feature a smooth, rounded mushroom head and a square neck underneath that prevents the bolt from turning when the nut is tightened, making them ideal for wood-to-wood and wood-to-metal security applications.

• American Size (# Gauge/Inch)	Nearest Metric Size (M)	Head Diameter (dk) (mm/inch)	Square Neck Width (v) (mm/inch)	Head Height (k) (mm/inch)
  #10 - 24	M5	13.5 mm / 0.469"	5.0 mm / 0.199"	3.3 mm / 0.114"
  1/4" - 20	M6	16.5 mm / 0.594"	6.0 mm / 0.260"	3.8 mm / 0.145"
  5/16" - 18	M8	20.6 mm / 0.719"	8.0 mm / 0.324"	4.8 mm / 0.176"
  3/8" - 16	M10	24.6 mm / 0.844"	10.0 mm / 0.388"	5.3 mm / 0.208"
  1/2" - 13	M12	30.6 mm / 1.094"	12.0 mm / 0.518"	6.9 mm / 0.270"
  5/8" - 11	M16	38.8 mm / 1.344"	16.0 mm / 0.650"	8.9 mm / 0.344"
  3/4" - 10	M20	46.8 mm / 1.594"	20.0 mm / 0.775"	11.0 mm / 0.406"

• Surface Treatment

• Coating	Process	Salt Spray	Aplicativo
  Zinc Plated	Electroplating	72 to 144h	Indoor Furniture / Shelving
  Hot-Dip Galvanized	Molten Zinc	500 to 800h	Outdoor Fencing / Infrastructure
  Black Oxide	Chemical	24 to 48h	Decorative Hardware / Interior
  Passivated	Chemical	1000+h	Food Industry / Marine