Holo-krome 72138 Hex Socket Cap Screw 5/16-18 Unc

Product Description

The HOLO-KROME 72138 is a hex socket cap screw sized at 5/16-18 UNC with a 2-1/4 inch length under the head. It is partially threaded and driven by a 1/4 inch hex key. Manufactured from alloy steel and finished with a black oxide coating, this fastener meets ASME B18.3 and ASTM A574 standards. The black oxide finish provides moderate corrosion resistance and reduces surface reflectivity. This screw is used in precision mechanical assemblies, HVAC equipment mounting, and general industrial fabrication where a flush or low-profile fastener head and high tensile strength are required.

This fastener suits residential and commercial applications where alloy steel socket cap screws are specified by design or maintenance requirements. Typical uses include equipment frames, motor mounts, bracket fastening, and panel assemblies across HVAC, plumbing, and light industrial equipment. The partially threaded shank provides clamping force and alignment in through-hole and threaded insert applications. This screw is sold in a minimum order quantity of 100 pieces per order.

Key Features

• Thread size 5/16-18 UNC for broad compatibility with standard UNC tapped holes
• 2-1/4 inch length under head with partial threading for positive clamping
• Alloy steel construction meets ASTM A574 high-strength fastener requirements
• Black oxide finish provides mild corrosion resistance and low-glare surface
• 1/4 inch hex socket drive for use with standard hex keys and socket drivers
• Conforms to ASME B18.3 dimensional standards

Compatibility

Designed as a standard UNC hex socket cap screw for use in any application requiring a 5/16-18 threaded fastener conforming to ASME B18.3 and ASTM A574 specifications.

Installation Notes

Installation requires a 1/4 inch hex key or T-handle driver. Ensure the mating tapped hole is clean and free of debris before driving. Follow applicable torque specifications from the equipment manufacturer or relevant fastener standards for alloy steel cap screws. Power down and de-energize any equipment before accessing fastener locations on live assemblies.