Holo-krome 72378 Hex Socket Cap Screw 1-8 Unc Alloy Steel

Product Description

The HOLO-KROME 72378 is a hex socket cap screw engineered for high-strength fastening in demanding mechanical and industrial assemblies. Sized at 1-8 UNC thread with a 3.25-inch length under head, this screw is fully threaded and driven with a 3/4-inch hex key. The alloy steel construction delivers the tensile strength required for structural connections, and the black oxide finish provides moderate corrosion resistance while reducing surface glare. It meets ASME B18.3 and ASTM A574 standards, making it a recognized specification-grade fastener used by maintenance technicians, millwrights, and mechanical contractors.

This fastener is suited for machine assembly, structural bolting, equipment mounting, and retrofit applications where a recessed hex drive is preferred over an external hex head. The 1-8 UNC coarse thread pattern allows faster installation and performs well in tapped holes in steel, cast iron, and aluminum. Fully threaded along the shank length, it provides clamping engagement across the full grip range, which is useful in thinner material stacks or adjustable-depth applications common in HVAC equipment frames, pump bases, and electrical enclosure assemblies.

Key Features

• 1-8 UNC coarse thread for fast engagement in standard tapped holes
• 3.25-inch length under head with full-thread shank for maximum clamping range
• 3/4-inch hex socket drive for use with standard hex keys or Allen-drive tooling
• Alloy steel construction meets ASTM A574 high-strength requirements
• Black oxide finish provides mild corrosion resistance and low-glare surface
• Conforms to ASME B18.3 dimensional standards for interchangeability

Compatibility

Designed as an ASME B18.3 and ASTM A574 specification-grade hex socket cap screw suitable for standard 1-8 UNC tapped holes in mechanical, structural, and equipment assembly applications.

Installation Notes

Installation is typically performed by millwrights, maintenance mechanics, or mechanical contractors using a calibrated torque wrench with a 3/4-inch hex bit or a standard 3/4-inch Allen key. Ensure the receiving tapped hole is clean, free of debris, and cut to the correct thread class before installation. De-energize and lock out any equipment before fastener service on live machinery per applicable OSHA lockout/tagout procedures. Do not substitute a lower-grade fastener in applications specifying ASTM A574.