Holo-krome 72358 Hex Socket Cap Screw 7/8-9 Unc Alloy Steel

Product Description

The HOLO-KROME 72358 is a hex socket cap screw designed for high-strength fastening applications requiring a compact drive profile. Sized at 7/8-9 UNC with a 5.5-inch length under head, this fastener is partially threaded and driven with a 3/4-inch hex (Allen) key. Constructed from alloy steel with a black oxide finish, it meets ASME B18.3 and ASTM A574 standards, making it suitable for demanding mechanical assemblies where tensile strength and dimensional precision are critical. Maintenance technicians, millwrights, and industrial contractors working on heavy equipment, machinery frames, and structural assemblies are the primary installers.

This screw is well suited for industrial and commercial applications where socket cap fasteners are preferred over hex head bolts due to limited wrench clearance. The partially threaded shank provides a grip length that helps maintain joint clamping force without thread engagement in the bearing area. Typical installations include machine bases, hydraulic manifold mounting, fabricated steel assemblies, and equipment housings where controlled torque and flush or recessed fastener heads are required.

Key Features

• 7/8-9 UNC thread size for high-load fastening
• 5.5-inch length under head with partial threading for accurate grip-length control
• 3/4-inch hex socket drive for high-torque installation in tight clearances
• Alloy steel construction meets ASTM A574 mechanical property requirements
• Black oxide finish provides mild corrosion resistance and reduces light reflection
• Meets ASME B18.3 dimensional standards for socket cap screws

Compatibility

Designed as an OEM-style and aftermarket replacement hex socket cap screw conforming to ASME B18.3 and ASTM A574, suitable for any application specifying a 7/8-9 UNC partially threaded socket cap screw with a 5.5-inch length under head.

Installation Notes

Installation should be performed by a qualified millwright, maintenance mechanic, or industrial technician familiar with fastener torque procedures. De-energize and lock out all equipment before removing or replacing structural fasteners. Use a calibrated torque wrench with a 3/4-inch hex bit to achieve proper clamp load; consult the equipment manufacturer's torque specification for the joint. Avoid cross-threading by starting the fastener by hand before applying drive torque.