Description
1-1/4"-7 L9 Hex Head Cap Screw – Coarse Thread Alloy Steel Zinc Yellow CR+3 (Made in U.S.A.)
Introducing our premium 1-1/4"-7 L9 (L-9) Hex Head Cap Screws, the ultimate solution for high-stress applications requiring maximum strength and reliability. Engineered for unmatched performance, these bolts are made in the USA from high-grade alloy steel and boast exceptional mechanical properties, including a tensile strength of 180,000 PSI—the highest in the industry.
Why Choose Our L9 Hex Head Cap Screws?
L-9 (L9) fasteners represent the pinnacle of SAE grading for hex cap screws, designed to withstand extreme loads and stress conditions. Identified by "L9" and nine radial lines on the head, these screws ensure easy recognition of their superior grade. The coarse thread (UNC) design offers excellent resistance to stripping and is ideal for quick assembly and disassembly. The Zinc Yellow CR+3 plating provides enhanced corrosion resistance and a professional finish.
Enhanced Design Features:
- Increased Head Height: Slightly higher head height compared to standard hex cap screws per ASME B18.2.1, allowing for better wrench contact and reduced slippage.
- Radius Under Head: Adds strength by reducing stress concentrations, minimizing the risk of fatigue failure.
- Smooth Washer-Bearing Surface: Ensures even load distribution and reduces the risk of loosening under dynamic loads.
Key Mechanical Properties:
- Hardness: 38 to 42 HRC (Rockwell Hardness Scale)
- Surface Hardness: Maximum HR15N 81.5
- Tensile Strength: Minimum 180,000 PSI, Maximum 200,000 PSI
- Yield Strength: 155,000 PSI Minimum
- Proof Load Strength: 145,000 PSI
- Elongation: 12% Minimum
- Reduction of Area: 35% Minimum
- Head Marking: Identified by "L9" and nine radial lines for easy grade recognition
Advanced Surface Finish:
- Zinc Plated Yellow Finish: Conforms to ASTM F1941/F1941M Fe/Zn 5CN specifications, with a minimum plating thickness of 5 microns (0.0002").
- Yellow Trivalent (Cr+3) Coating: Provides superior corrosion resistance, offering up to 96 hours of protection before red rust appears in salt spray testing.
Technical Specifications:
- Size: 1-1/4"-7 (Diameter: 1.250", Threads per Inch: 7)
- Length Options: Available in various lengths to suit your specific needs (please select from the options above)
- Material: High-Grade Alloy Steel (Grade L-9 / L9)
- Finish: Zinc Yellow CR+3 Plating for enhanced corrosion resistance
- Tensile Strength: Minimum 180,000 PSI
- Thread Type: Coarse Thread (UNC)
- Standards: Meets or exceeds SAE J429 Grade L-9 and ASME B18.2.1 specifications
- Manufactured In: United States of America
Ideal Applications:
Our 1-1/4"-7 L-9 (L9) Hex Head Cap Screws with coarse threads are perfect for applications where maximum strength and ease of assembly are critical. They are ideal for heavy machinery, construction equipment, structural assemblies, and other demanding industrial applications where reliability is paramount.