Heavy Hex Bolts are designed for use in a variety of high temperature, high strength industrial applications, such as with steel fabrication and general construction. They feature a thicker head than standard or regular hex bolts, and offer a greater bearing surface that distributes the clamping load over a wider area.
HOT DIP GALVANISED : IS 1367 PT 13 IS: 4759 BS EN: 1461, ASTM A153 ASTM A123 BLACK PHOSPHATE: IS 1367 PT 12 ELECTRO GALVANISED : IS: 1367 PT 11 , IS: 1573 PTFE COATING: ASTM D:3294
WE CAN MANUFACTURE ANY TYPE OF TYPICAL FASTENERS AS PER CUSTOMER DRAWING AND SPECIFICATIONS.
Important Message for our Customers
It is requested to buy direct from the company or see the invoice or documentary evidence from the dealer to ensure that you are buying genuine products of TUFF. We come to know that some Traders are supplying TUFF BRAND products while manufacturing at their own using inferior quality raw materials.
Product Specifications
As per national and international standards
Parameter
Specification
Size Range
M16M18M20M22M24M27M30M33M36
Property Classes
PC 8SPC 10SASTM A490 Type 1ASTM F3125 Grade A490ASTM A193 Grade B7ASTM A320 Grade L7/L7MASTM A193 Grade B8/B8M
ISO 10684 — Hot dip galvanized coatings for fasteners
ISO 4042 — Electroplated coating systems for fasteners
ISO 10683 — Non-electrolytically applied zinc flake coatings
ISO 1461 — Hot dip galvanized coatings on fabricated iron articles
🌏 International & Regional
AS/NZS 1252 — Structural bolts (AU/NZ)
ASTM F3393 — PTFE coating specification
Applications
Engineered for critical connections across heavy industry and infrastructure
Steel Fabrication & Bridges
Power Plants & Transmission Towers
Oil & Gas Infrastructure
Heavy Engineering & Machinery
Petrochemical & Refinery Plants
Road & Highway Infrastructure
Metro & Mass Transit Projects
Structural Steel Buildings
Ports & Marine Structures
Aerospace & Defence Equipment
Frequently Asked Questions
Common questions about TUFF Heavy Hex Bolt
What distinguishes Heavy Hex from standard Hex Bolt?+
Heavy Hex Bolts have a larger head diameter and thickness than standard hex bolts of the same nominal size, per IS 3757 / ASME B18.2.6 / EN 14399-3. This provides a wider bearing surface — critical in heavy structural steel construction. Standard bolts under ISO 4014 or ISO 4016 utilize normal head dimensions.
What does EN 14399-3 (System HR) cover?+
EN 14399-3 specifies System HR high-strength structural bolting assemblies for preloading in steel structures. It is the primary European standard for heavy hex bolt applications built to Eurocode specifications.
Are your Heavy Hex Bolts available in Property Class 10S?+
Yes. We manufacture heavy hex structural bolts in high-strength property classes such as 8S and 10S conforming to IS 3757 / IS 1367 Pt.3 to support heavy structural mechanical load specifications.
Do you supply with Hot Dip Galvanized (HDG) finish?+
Yes. We provide Hot Dip Galvanized coatings precisely matching strict fastener processing criteria under ISO 10684, IS 1367 Pt.13, and ASTM F2329/F2329M to ensure structural thread compliance and uniform rust protection.
Can you supply with material test reports and third-party inspection?+
Yes. Full MTRs (chemical and mechanical) are provided for every batch. Third-party inspection by agencies such as Bureau Veritas, SGS, or TÜV can be facilitated on request.
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