Holo-krome 73158 Hex Socket Cap Screw 5/8-18 Unf

Product Description

The HOLO-KROME 73158 is a partially threaded hex socket cap screw designed for high-strength fastening applications. Sized at 5/8-18 UNF with a 2-3/4 inch length under head, it uses a 1/2 inch internal hex drive for installation with a standard Allen or hex key. The fastener is manufactured from alloy steel and finished with a black oxide coating, which provides moderate corrosion resistance and reduces light reflection in service environments. It conforms to ASME B18.3 and ASTM A574 standards, making it appropriate for structural and mechanical assemblies where tensile strength and dimensional consistency are required.

This cap screw is suited for use in industrial machinery, mechanical assemblies, equipment frames, and fabricated components that require a recessed-drive, high-strength fastener. The partial thread design allows for clamping force through an unthreaded shank section, which is standard practice in joints where shear load is a primary concern. Licensed mechanical contractors, millwrights, machinists, and field technicians working on HVAC equipment frames, pump assemblies, and structural brackets will find this fastener appropriate for those applications.

Key Features

• 5/8-18 UNF thread size for fine-thread engagement and higher thread strength per diameter
• 2-3/4 inch length under head with partial threading for shear-load joints
• 1/2 inch hex socket drive compatible with standard Allen keys and hex bit drivers
• Alloy steel construction meets ASTM A574 high-strength socket cap screw requirements
• Black oxide finish for moderate corrosion resistance and low-reflectance appearance
• Conforms to ASME B18.3 dimensional standards

Compatibility

Designed as a standard ASME B18.3 hex socket cap screw suitable for use in any application requiring a 5/8-18 UNF partially threaded fastener with a 1/2 inch hex drive.

Installation Notes

Install using a 1/2 inch hex key or hex bit driver; do not use an undersized driver as it will damage the socket. Ensure mating threads are clean and free of debris before installation. Verify that the receiving tapped hole or nut meets the torque and thread engagement requirements specified by the assembly design. Follow applicable ASME or equipment manufacturer torque specifications for 5/8-18 UNF alloy steel fasteners when finalizing the joint.