Meet the HILLMAN 7/8-9 in. D X 3-1/2 in. L Heat Treated Steel Hex Head Cap Screw—built for serious strength in demanding metal-to-metal assemblies. Crafted from steel and heat-treated to Grade 8 standards, this fastener is designed to resist deformation under heavy loads, delivering dependable clamping power where it counts.
What makes this screw different
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Diameter and thread: 7/8 inch diameter with a 9 TPI coarse thread for quick, confident thread engagement in thick materials.
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Length: 3-1/2 inches, providing ample bite for through-hole or thick components while maintaining a strong shank for shear resistance.
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Head style: Hex head for easy driving with standard wrenches or sockets, even in tighter spaces.
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Material and treatment: Heat-treated steel offers enhanced hardness and fatigue resistance, ideal for high-stress applications.
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Grade: Grade 8 construction delivers superior strength compared to common fasteners, reducing the risk of thread stripping in demanding environments.
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Point type: Blunt tip designed for controlled alignment and clean entry in through-holes, minimizing misalignment during installation.
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Packaging: Boxed packaging, with a 10-piece count, making it convenient to stock up for ongoing projects.
Ideal uses and real‑world benefits
Designed for serious projects that demand reliable performance, this Hillman hex head cap screw shines in:
- Heavy-duty frame and trailer components where thick metal members must be securely fastened.
- Machinery mounting, equipment housings, and industrial fixtures that require high clamp load and steadfast retention.
- Fabrication or repair work on automotive and agricultural equipment where a robust, long-lasting fastener is essential.
- Construction and shop fabrication tasks involving thick plates or structural members that benefit from Grade 8 strength.
Performance you can trust
Compared with lower-grade fasteners, this Hillman screw delivers improved resistance to shear and tensile forces, helping you avoid premature wear and loosening over time. The combination of a coarse thread and blunt point makes installation faster and more forgiving in tougher materials, while the hex head enables secure, precise torque with common hand tools or impact drivers.
Practical tips for best results
- Pair with compatible lock washers or anti-vibration solutions when vibration is a factor in your application.
- Ensure hole diameters and through-holes match your 7/8" diameter screw to optimize engagement and clamp load.
- Use the right torque range for Grade 8 steel to maximize clamping force without risking damage to threads.
- Store in the boxed packaging to preserve thread cleanliness and prevent damage during transit or storage.
