National Hardware N273-920 Concealed Surface Mortise Hinge

Product Description

The NATIONAL HARDWARE N273-920 is a concealed surface mortise hinge designed for door applications requiring a clean, low-profile installation. Constructed from steel with a plain steel finish, this hinge features a 4-inch overall width and a 5-knuckle barrel for smooth, durable pivot action. It carries a 70-pound load capacity, making it suitable for standard interior doors in residential and light commercial settings. The surface mortise mount type allows installation without deep mortising into the door or frame, reducing labor time on the job. Typically installed by finish carpenters, millwork contractors, or general contractors during door hanging or hinge replacement work.

This hinge is suited for interior door installations where a concealed, flush-mounted appearance is required. The 4-inch door and frame leaf height with a 2-inch leaf width on both sides provides a balanced bearing surface for standard door weights up to 70 pounds. It is appropriate for residential entry doors, interior passage doors, and cabinet doors in both new construction and remodel applications. Install crews working on door hardware replacements or upgrades will find this hinge straightforward to fit using standard hand tools.

Key Features

• Surface mortise mount type reduces need for deep door or frame routing
• 5-knuckle barrel design provides smooth operation and increased bearing support
• 70-pound load capacity suits standard residential interior door weights
• Matching 4-inch height on both door and frame leaf for symmetrical installation
• Plain steel finish accepts paint or primer for finished applications
• Steel construction provides lasting durability in interior door applications

Compatibility

Designed as an OEM-style replacement or new-installation surface mortise hinge for standard residential and light commercial interior doors requiring a 4-inch, 5-knuckle concealed hinge with a 70-pound load rating.

Installation Notes

Installation should be performed by a qualified carpenter or door hardware technician. Ensure the door is properly supported and all fasteners from the existing hinge are fully removed before fitting the new hinge. Use a drill and appropriate bit for pilot holes to prevent wood splitting; do not overdrive fasteners. Follow applicable building codes for door hardware installation in commercial environments.