High-Strength 1 1/8" Hex Head Bolts for Demanding Industrial Applications
Engineered for critical connections where failure is not an option, our 1 1/8 hex head bolts represent the pinnacle of heavy-duty fastening solutions. Designed to meet and exceed international standards, these large-diameter bolts provide unparalleled clamping force, shear strength, and durability in the most challenging environments. Whether for structural steel, heavy machinery, or infrastructure projects, understanding the precise 1 1 8 hex head bolt dimensions and specifications is crucial for ensuring project integrity, safety, and longevity.
Product Overview
Our 1 1/8" (inch) hex head bolts are manufactured from high-grade alloy steel, undergoing rigorous heat treatment to achieve superior mechanical properties. The prominent hex head design allows for high-torque installation with standard wrenches, ensuring a secure and reliable fit. These bolts are available in a full range of lengths, thread pitches (UNC/UNF), and finishes—including hot-dip galvanized, plain, and zinc-plated—to combat corrosion and meet specific environmental and aesthetic requirements. Precise adherence to 1 1 8 hex head bolt dimensions guarantees compatibility and interchangeability in global industrial applications.
Key Features
- Exceptional Strength Grades: Available in Grade 5, Grade 8, and ASTM A325/A490 equivalents, offering tensile strengths up to 150 ksi for the most demanding loads.
- Precision Engineering: Consistent thread rolling and machining ensure perfect fit and optimal load distribution, critical for the specified 1 1 8 hex head bolt dimensions.
- Superior Corrosion Resistance: Multiple coating options provide long-term protection against rust, chemicals, and harsh weather conditions.
- Rigorous Quality Assurance: Each batch is tested for hardness, tensile strength, and dimensional accuracy, with full traceability and certification available (e.g., Mill Test Certificates).
- Global Compliance: Manufactured to meet ANSI, ASME, ISO, DIN, and other international standards, ensuring worldwide acceptance.
Technical Specifications
| Parameter | Specification | Details / Standard |
|---|---|---|
| Nominal Diameter (D) | 1 1/8 Inch | 28.575 mm |
| Thread Pitch | 7 UNC or 8 UNF | Common standard: 7 Threads Per Inch (UNC) |
| Hex Head Width (A/F) | 1 11/16" | ~42.86 mm (Across Flats) |
| Hex Head Height | 11/16" | ~17.46 mm |
| Common Lengths (L) | 3" to 24" + | Measured from under-head to thread end. Custom lengths available. |
| Material | Alloy Steel (e.g., 4140, 8740) | Medium Carbon Steel or Boron Steel |
| Strength Grade | Grade 5, Grade 8, ASTM A325, A490 | Tensile: 120 ksi min. (Grade 8), 150 ksi min. (A490) |
| Finish / Coating | Plain, Zinc-Plated, HDG, Dacromet | Hot-Dip Galvanized per ASTM A153 |
| Standards | ASME B18.2.1, ASTM F3125 | Compliant with ISO 4014 / DIN 933 |
Note: The above 1 1 8 hex head bolt dimensions are standard. Contact our engineering team for custom or non-standard specifications.
Application Scenarios
The robust design and significant load-bearing capacity of 1 1/8" hex bolts make them indispensable across heavy industries. Key applications include:
- Structural Steel Construction: Primary connections in bridges, high-rise buildings, and industrial plant frameworks.
- Heavy Machinery & Mining Equipment: Critical assembly points in excavators, crushers, conveyor systems, and draglines.
- Power Generation & Renewable Energy: Flange connections in wind turbine towers, boiler structures, and transformer bases.
- Transportation Infrastructure: Fastening for guardrails, sign supports, and large-scale fabrication in rail and port facilities.
- Oil, Gas, & Petrochemical: Pressure vessel assemblies, pipeline flanges, and offshore platform structures requiring high integrity.
Advantages
Choosing our 1 1/8" hex head bolts delivers tangible benefits to your project's bottom line and performance:
- Optimized Load Distribution: The large bearing surface under the hex head minimizes surface pressure, preventing material deformation.
- Simplified Installation & Maintenance: Standard hex drive allows for fast installation with common tools, reducing labor time and cost.
- Enhanced Safety Margin: Manufactured with a consistent safety factor above rated strength, providing a reliable buffer against dynamic or unexpected loads.
- Long-Term Cost Efficiency: Superior materials and coatings drastically reduce the frequency of inspections, maintenance, and replacements due to corrosion or fatigue.
- Supply Chain Reliability: Consistent inventory of standard 1 1 8 hex head bolt dimensions and the ability to fulfill large, custom orders on schedule.
Why Choose Us
As a leading supplier in the industrial fasteners sector, we differentiate ourselves through unwavering commitment to quality and service:
- Deep Technical Expertise: Our team provides pre-sales engineering support to help you select the optimal bolt grade, coating, and 1 1 8 hex head bolt dimensions for your specific application.
- End-to-End Quality Control: From raw material sourcing to final packaging, our in-house QC ensures every bolt meets stringent dimensional and mechanical specifications.
- Global Logistics Network: We efficiently handle bulk shipments worldwide, ensuring your fasteners arrive on-site when you need them, supported by comprehensive documentation.
- Custom Manufacturing Capability: Beyond standard sizes, we specialize in producing custom-length, non-standard thread, and specially hardened bolts to your exact drawings.
- Trusted Partner for Major Projects: Our products are specified and trusted by OEMs, construction firms, and engineering consultancies on critical infrastructure projects globally.
FAQ
What is the standard thread pitch for a 1 1/8" hex bolt?
The most common (UNCoarse) thread pitch for a 1 1/8" diameter bolt is 7 threads per inch (7 UNC). An 8 UNF (Fine) thread is also available for applications requiring finer adjustment or higher fatigue resistance.
What wrench size is required for a 1 1/8" hex head bolt?
Per standard 1 1 8 hex head bolt dimensions, the across-flats (A/F) width is 1 11/16 inches (approx. 42.86 mm). You will need a 1 11/16" wrench or socket. A 43mm metric socket is a very close alternative.
What is the difference between Grade 5 and Grade 8 for this size?
Grade 8 bolts have a higher minimum tensile strength (150 ksi) and proof load compared to Grade 5 (120 ksi). Grade 8 is used for critical, high-stress applications, while Grade 5 is suitable for general heavy-duty purposes. Material and heat treatment processes differ accordingly.
Do you provide corrosion-resistant options for marine environments?
Absolutely. For severe environments, we recommend Hot-Dip Galvanized (HDG) to ASTM A153 or specialized coatings like Dacromet 3200 (Geomet) or Xylan. These provide exceptional sacrificial protection against saltwater and chemical exposure.
Can I order custom lengths or with specific markings?
Yes. We regularly manufacture bolts in non-standard lengths and can apply head markings (grade identification, manufacturer's logo) as per customer requirements. Please provide your detailed specifications for a quotation.
Contact our sales engineering team today for a competitive quote, detailed technical data sheets, or to discuss your specific project requirements for 1 1 8 hex head bolt dimensions and specifications.