Product Summary

লংজে ক্যারেজ বোল্ট (also known as Coach Bolts or Cup Head Square Neck Bolts) are manufactured according to DIN 603 এবং 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 লংজে ক্যারেজ বোল্ট 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: লংজে 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 ক্যারেজ বোল্ট

• 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 মরিচা রোধক স্পাত.

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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

• উপাদান	শ্রেণী	Tensile Strength	Yield Strength	আবেদন
  Carbon Steel	4.8	420 MPa	340 MPa	General Woodworking
  Carbon Steel	8.8	800 MPa	640 MPa	Structural / Machinery
  মরিচা রোধক স্পাত	SS304 (A2)	$\ge 700$ MPa	$\ge 450$ MPa	Outdoor Decks / Furniture
  মরিচা রোধক স্পাত	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	এম১২	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	এম২০	46.8 mm / 1.594"	20.0 mm / 0.775"	11.0 mm / 0.406"

• Surface Treatment

• Coating	Process	Salt Spray	আবেদন
  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