Gibraltar 41803G 3/8-16 Steel Black Oxide Spherical Flange Nut

Product Description

The GIBRALTAR 41803G is a 3/8-16 spherical flange nut manufactured from 12L14 leaded steel with a black oxide finish. The spherical bearing surface under the flange allows the nut to seat evenly on angled or uneven mating surfaces, distributing clamping load without requiring a perfectly perpendicular fastener axis. The nut stands 0.5 inches high with a hex size of 0.6875 inches across flats. The integrated flange measures 0.875 inches in diameter and 0.125 inches high, with a spherical radius of 1.25 inches. Black oxide provides mild corrosion resistance and reduces galling during installation. Licensed mechanical contractors, maintenance technicians, and fabricators will encounter this fastener in structural and mechanical assembly applications.

This spherical flange nut is suited for mechanical assemblies where bolt alignment cannot be guaranteed perpendicular to the clamping surface. Typical applications include brackets, frames, machinery mounts, and industrial fixtures where vibration or angular misalignment is a factor. The 3/8-16 UNC thread is one of the most common coarse-thread sizes in trade and industrial fastener work. The 12L14 steel grade offers good machinability and consistent thread engagement. This part ships in a minimum order quantity of 5 units and is packaged as a single-count unit.

Key Features

• Spherical flange bearing surface accommodates angular misalignment without losing clamping force
• 12L14 leaded steel construction provides reliable thread engagement and machinability
• Black oxide finish reduces surface friction and provides mild corrosion protection
• 3/8-16 UNC coarse thread — standard trade size with broad tool compatibility
• Integrated flange eliminates the need for a separate washer in most applications
• Meets TCMAI standards for dimensional and material consistency

Compatibility

Designed for use with 3/8-16 UNC threaded fasteners in standard mechanical, structural, and industrial assembly applications requiring a spherical flange nut.

Installation Notes

Installation is performed with a standard 0.6875-inch hex wrench or socket. Clean mating threads and inspect for damage before assembly. Torque to the value specified in the assembly drawing or equipment service manual — do not assume a torque value. Black oxide finish is not a substitute for anti-corrosion coatings in wet or outdoor environments; apply thread lubricant or sealant as required by the application.