National Mfg N351-023 4in Satin Nickel Spring Door Hinge Ul

Product Description

The NATIONAL MFG/SPECTRUM BRANDS HHI N351-023 is a 4-inch satin nickel spring adjustable door hinge designed for both standard and fire-rated door applications. Built from cold rolled steel, this hinge features independently adjustable closing speed and spring tension, allowing installers to dial in door behavior without swapping hardware. The 5/8-inch radius round corners fit standard hinge cutouts directly. UL approval for fire doors makes it suitable where code-required fire-rated assemblies are specified. The package includes 2 hinges per unit.

This hinge is used in residential and light commercial door installations where a self-closing function is required. It is well suited for interior doors that must meet fire door assembly requirements, including corridor doors, stairwell access doors, and utility room entries. The adjustable tension and closing speed make it adaptable across a range of door weights and swing scenarios without requiring a separate door closer unit.

Key Features

• Adjustable closing speed allows field-tuning without replacing the hinge
• Adjustable spring tension accommodates varying door weights and swing resistance
• Cold rolled steel construction for durability in high-cycle applications
• 5/8-inch radius round corners fit standard hinge cutouts with no mortise modification
• UL approved for fire door assemblies where self-closing hardware is code-required
• Satin nickel finish for corrosion resistance and neutral aesthetic

Compatibility

Designed as an OEM-style replacement or new-installation hinge for standard 4-inch hinge cutout door preparations on residential and light commercial doors, including UL-listed fire door assemblies.

Installation Notes

Installation is typically performed by a finish carpenter, door hardware installer, or general contractor. Ensure the door and frame are properly aligned before final installation to prevent binding that can affect spring tension performance. Consult local building codes and the door assembly listing requirements when installing on fire-rated assemblies, as the hinge must be part of a complete listed fire door assembly. Do not modify the spring mechanism in the field.