Description
The 5/16"-18 Flat Head Cap Screw is a medium-diameter, flush-mount fastener engineered for secure and low-profile installation in industrial, structural, and mechanical assemblies. Featuring an 82° countersunk flat head and internal hex drive, this screw allows for a smooth, surface-level finish while providing reliable torque control and strong thread engagement.
Specifications
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Thread Size: 5/16"-18 (Unified National Coarse)
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Head Type: Flat head with 82° countersink and internal hex drive
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Drive Type: Hex socket (Allen)
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Length: Available in standard lengths (typically from 1/2" to 3")
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Material: Available in alloy steel, stainless steel, black oxide, or zinc-plated carbon steel
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Finish Options: Black oxide, plain, zinc-plated, or stainless
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Grade: Typically Grade 8 (hardened alloy steel) or 18-8 / 316 stainless steel for corrosion resistance
Key Features
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Flush Surface Finish: Countersunk flat head allows for a smooth, unobtrusive installation ideal for tight clearances, moving components, or aesthetic surfaces.
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Reliable Strength: The 5/16" diameter and 18 TPI coarse thread offer excellent holding power for medium-load applications.
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Internal Hex Drive: Allen socket drive ensures accurate torque application with minimal risk of stripping or head deformation.
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Durable Finishes: Multiple material and coating options provide resistance to corrosion, abrasion, and wear in harsh environments.
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Precision Machining: UNC threading ensures tight, vibration-resistant mating with tapped holes or standard nuts.
Typical Applications
The 5/16"-18 Flat Head Cap Screw is commonly used in medium-duty mechanical and structural applications that require a clean surface finish:
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Machine Guarding and Panel Mounting
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Automotive and Motorcycle Trim
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Structural Frames and Enclosure Systems
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Safety Equipment and Access Doors
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Fixtures, Furniture, and Display Hardware
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Robotics, Tooling, and Modular Assemblies
