National Marker N350827 Spring Door Hinge 3.5 in Oil Rubbed Bronze

Product Description

The NATIONAL MARKER N350827 is a 3.5-inch oil rubbed bronze spring door hinge designed for self-closing door applications in residential, commercial, and multi-family buildings. Built from cold-rolled steel, this hinge installs into a standard hinge cutout and features a 1/4-inch radius round corner profile. It carries UL approval for use on fire-rated doors, making it a code-compliant choice where fire door assemblies are required. The adjustable closing speed mechanism allows for field tuning without replacing the unit. Typical applications include basement doors, stairway access doors, garage entry doors, and building entrances. This is catalog model V521 series.

This hinge is suited for both new construction and retrofit installations on self-closing doors in residential homes, apartment buildings, and light commercial facilities. Its standard hinge cutout fit means it drops into existing door prep without modification in most cases. The UL fire door listing makes it appropriate for locations where building code or insurance requirements mandate rated door assemblies, such as attached garage-to-living-space entries and stairwell enclosures. The adjustable spring tension accommodates varying door weights and closing force requirements.

Key Features

• UL approved for fire-rated door assemblies
• Adjustable closing speed for field tuning after installation
• Cold-rolled steel construction with oil rubbed bronze finish
• 1/4-inch radius round corner profile fits standard hinge cutouts
• Suitable for residential, commercial, and apartment building applications
• 3.5-inch hinge size for standard door hanging

Compatibility

Designed as an OEM-style replacement or new-installation spring hinge for standard residential and light commercial self-closing door applications requiring a 3.5-inch hinge with a 1/4-inch radius corner profile.

Installation Notes

Installation is typically performed by a finish carpenter, general contractor, or qualified maintenance technician. The door and frame should be properly supported before removing any existing hardware. Refer to the local applicable building code and the door manufacturer fire label requirements when installing on fire-rated assemblies. Adjust the spring tension only with the door fully hung and hardware secured, following the manufacturer adjustment procedure for the V521 series.

Technical Specifications

• Hinge Size: 3.5 inches
• Corner Radius: 1/4 inch
• Material: Cold-rolled steel
• Finish: Oil rubbed bronze
• Closing Speed: Adjustable
• UL Listed: Yes, fire door rated
• Catalog Series: V521
• Weight: 0.799 pounds
• UPC: 00038613350823

Standard Information

• Brand: NATIONAL MARKER
• Manufacturer Part Number: N350827