Value Collection 99039 5/16-18 X 3-1/2 in Grade 8 Hex Cap Screw

Product Description

The VALUE COLLECTION 99039 is a Grade 8 steel hex head cap screw with a 5/16-18 UNC thread and a 3-1/2 inch length under head. It features partial threading and an uncoated finish, conforming to ASME B18.2.1 dimensional standards. Grade 8 steel delivers high tensile and proof load strength, making this fastener suitable for demanding structural and mechanical assemblies. These screws are sold in a pack of 100 and are intended for use by maintenance technicians, millwrights, HVAC installers, and other trade professionals who need a reliable, spec-compliant fastener in inch sizing.

This hex head cap screw is well suited for residential and light commercial mechanical applications where a high-strength inch-series fastener is required. The 5/16-18 coarse thread pattern seats quickly and holds firmly in steel, cast iron, and similar materials. Partial threading allows for clamping force across unthreaded shanks, which is useful in bolted joint assemblies where precise load distribution matters. The uncoated finish is appropriate for indoor or protected installations where corrosion resistance is not a primary concern.

Key Features

• Grade 8 steel construction for high proof load and tensile strength
• 5/16-18 UNC coarse thread for broad compatibility with standard inch fastener hardware
• 3-1/2 inch length under head for deep-reach bolted joint applications
• Partially threaded shank allows controlled clamping force distribution
• Conforms to ASME B18.2.1 hex head cap screw dimensional standard
• Pack of 100 units minimizes restocking interruptions on active job sites

Compatibility

Designed as a standard inch-series hex head cap screw compatible with any 5/16-18 UNC tapped hole or matching nut in residential, commercial, or industrial mechanical assemblies.

Installation Notes

Installation is performed by maintenance technicians, millwrights, or mechanical contractors using a standard hex wrench or socket set. Always de-energize or lock out equipment before fastener replacement in live mechanical or electrical assemblies, per applicable OSHA lockout/tagout procedures. Do not mix Grade 8 fasteners with lower-grade nuts or hardware, as mismatched grades can compromise joint integrity. Verify thread engagement depth meets engineering requirements before torquing to final specification.