Soss 418US19 Heavy Duty Fire Rated Invisible Hinge Black

Product Description

The SOSS 418US19 is a heavy-duty, fire-rated invisible hinge engineered for 1.75-inch doors in applications where concealed hardware is required. Constructed from alloy steel with a black finish, this hinge installs fully within the door and frame, leaving no exposed hardware when the door is closed. The 418US19 carries a fire rating, making it suitable for fire-rated door assemblies where code compliance is a priority. Installation is typically performed by carpenters, finish contractors, or door hardware specialists working on commercial or high-end residential projects.

The 418US19 is designed for use with 1.75-inch doors and fits applications where a clean, hardware-free appearance is required on both the door face and the frame. Invisible hinges are commonly specified in commercial office environments, hospitality interiors, residential flush door installations, and any project where aesthetics demand that hinge hardware remain completely hidden. The fire-rated construction broadens its suitability to corridors, stairwells, and other code-governed openings.

Key Features

• Fully concealed design — no visible hardware when door is closed
• Fire-rated construction for use in code-compliant door assemblies
• Heavy-duty alloy steel build for durability in high-cycle applications
• Black finish for a clean, uniform appearance on dark door and frame stock
• Designed specifically for 1.75-inch door thickness

Compatibility

Designed as an OEM-style replacement or new-installation invisible hinge for 1.75-inch fire-rated and standard interior door assemblies requiring concealed hardware.

Installation Notes

Invisible hinges require precise mortising into both the door edge and the door frame — a router with a manufacturer-supplied template is the standard installation method. Power down any access-control or door-automation hardware before beginning work. Follow applicable building and fire codes, including door assembly listing requirements, when installing on rated openings. Confirm the door assembly fire label remains intact and undamaged after mortising.