Gibraltar 42205G Heavy Hex Jam Nut 1/2-13 Unc Alloy Steel

Product Description

The GIBRALTAR 42205G is a heavy hex jam nut designed for use in fastening assemblies that require a low-profile locking or locking-backup nut configuration. Manufactured from alloy steel with a black oxide finish, this nut features a 1/2-13 UNC right-hand thread and measures 7/8 inches across the flats and 19/64 inches in height. The heavy hex body provides greater wrench engagement and bearing surface compared to a standard hex jam nut, making it a reliable choice for structural and mechanical fastening applications where vibration resistance or a jam-nut setup is specified.

This nut is suited for general industrial, mechanical, and structural fastening work where a 1/2-13 UNC threaded connection is required. It is commonly used as a jam nut to lock a full hex nut in place, or in applications where a thin profile is needed to meet assembly clearance requirements. Trades including millwrights, pipefitters, ironworkers, and maintenance technicians regularly specify heavy hex jam nuts in both light industrial and heavy-duty equipment assemblies.

Key Features

• Heavy hex profile delivers extra wrench surface area for improved torque control
• Alloy steel construction provides high tensile strength for demanding fastening applications
• Black oxide finish offers mild corrosion resistance and reduces light reflection
• 1/2-13 UNC right-hand thread is a widely used coarse-thread standard for North American fastener applications
• Low-profile jam nut geometry suits tight-clearance assemblies and jam-nut locking configurations

Compatibility

Designed as a standard 1/2-13 UNC heavy hex jam nut suitable for use with any 1/2-13 UNC threaded fastener, rod, or stud conforming to ASME or ANSI heavy hex jam nut dimensional standards.

Installation Notes

Installation is performed using a standard wrench sized for 7/8-inch across-flats heavy hex fasteners. When used as a jam nut, thread the jam nut onto the stud or bolt first, install the full hex nut above it, and torque both nuts against each other to lock the assembly. Ensure the mating threaded component is free of burrs, corrosion, and debris before assembly. Always de-energize or lock out any equipment before performing fastener maintenance or replacement in live systems.