Holo-krome 77548 Hex Socket Cap Screw 1/2-20 Unf

Product Description

The HOLO-KROME 77548 is a partially threaded hex socket cap screw designed for high-strength fastening applications. It carries a 1/2-20 UNF thread and measures 5 inches under the head. The 3/8-inch hex drive socket accepts a standard hex key or Allen-style driver. Manufactured from alloy steel with a black oxide coating, this screw meets ASME B18.3 and ASTM A574 standards, making it suitable for precision mechanical assemblies, industrial equipment, and structural connections where tensile strength and tight dimensional tolerances are required. Installation is typically performed by millwrights, maintenance technicians, or mechanical contractors.

This screw is suited for use in industrial machinery, equipment frames, tooling fixtures, and precision-fit mechanical assemblies. The partially threaded shank provides a smooth bearing surface for applications that require shear resistance or close-tolerance shaft alignment. The 1/2-20 UNF fine thread pitch provides improved clamping force and is well matched to applications involving vibration or fine adjustment of clamped components. Black oxide finish provides mild corrosion resistance in controlled indoor environments.

Key Features

• 1/2-20 UNF fine thread for improved clamping force and vibration resistance
• 5-inch length under head with partial threading for shear-resistant shank section
• 3/8-inch hex drive socket compatible with standard hex keys and drivers
• Alloy steel construction meeting ASTM A574 high-strength requirements
• Black oxide coating for mild corrosion resistance and reduced light reflection
• Conforms to ASME B18.3 dimensional standard for socket cap screws

Compatibility

Designed as an OEM-style replacement or direct-fit fastener for applications requiring a 1/2-20 UNF partially threaded hex socket cap screw conforming to ASME B18.3 and ASTM A574.

Installation Notes

Install using a calibrated 3/8-inch hex key or T-handle driver; do not use an undersized driver as it will round the socket. De-energize and lock out all equipment before fastener service per applicable safety codes. Verify mating thread condition and thread engagement depth before final torque to avoid galling or cross-threading. Apply thread lubricant or thread-locking compound only as specified by the equipment manufacturer.