Holo-krome 73138 Hex Socket Cap Screw 1/2-20 Unf Alloy Steel

Product Description

The HOLO-KROME 73138 is a hex socket cap screw designed for high-strength fastening applications in mechanical assemblies, equipment maintenance, and industrial fabrication. It features a 1/2-20 UNF thread size with a 2-inch length under head and is fully threaded along its entire shaft. A 3/8-inch hex drive socket is required for installation. Manufactured from alloy steel with a black oxide finish, the 73138 meets ASME B18.3 and ASTM A574 standards, making it suitable for load-bearing and torque-critical connections across a wide range of trade and industrial uses.

This screw is used in mechanical, HVAC, plumbing, and electrical panel assemblies where a flush or low-profile fastener head and high clamp load are required. The 1/2-20 UNF fine thread pitch provides greater thread engagement and improved resistance to loosening under vibration compared to coarse thread equivalents. Licensed trades including HVAC technicians, pipefitters, and electricians commonly specify this fastener type when securing equipment frames, brackets, and access panels. It is sold in a minimum order quantity of 50 pieces per purchase.

Key Features

• 1/2-20 UNF fully threaded shaft for maximum thread engagement
• 2-inch length under head suits medium-depth fastening applications
• 3/8-inch internal hex drive accepts standard hex key and socket tooling
• Alloy steel construction meets ASTM A574 high-strength fastener requirements
• Black oxide coating provides mild corrosion resistance and reduces light reflection
• Conforms to ASME B18.3 dimensional standards for socket cap screws

Compatibility

Designed as an OEM-style and replacement fastener for mechanical assemblies requiring 1/2-20 UNF hex socket cap screws per ASME B18.3 dimensional standards.

Installation Notes

Installation is performed with a 3/8-inch hex key or socket driver; ensure the drive tool is fully seated before applying torque to avoid rounding the socket. De-energize or lock out any equipment before accessing fastened assemblies per applicable OSHA and NFPA 70E procedures. Inspect threads and mating surfaces for damage or contamination before assembly. Minimum order quantity of 50 pieces applies to this SKU.