Soss 218ICUS19 Invisible Spring Hinge Black 1-3/4 in Door

Product Description

The SOSS UIP ALLEGION 218ICUS19 is a heavy-duty invisible spring hinge designed for 1-3/4 inch thick doors, finished in black. When installed, the hinge is completely concealed within the door edge and frame, leaving no visible hardware on the door face. The spring mechanism provides automatic door return, making it well suited for high-traffic commercial and residential applications where a clean, hardware-free door appearance is required. Installed leaf dimensions measure 1-1/8 inches wide by 4-5/8 inches long. The unit ships as a single hinge and weighs approximately 2.9 pounds.

This invisible spring hinge is used in both residential and light commercial door installations where concealed hardware is specified — common in hospitality, office interiors, high-end residential millwork, and specialty door applications. Carpenters, finish carpenters, and door hardware installers typically work with this product. It is designed for use in 1-3/4 inch thick door applications and is sold individually.

Key Features

• Fully concealed when door is closed — no exposed knuckles or leaves on door face
• Integrated spring mechanism returns the door to closed position automatically
• Designed specifically for 1-3/4 inch door thickness
• Leaf dimensions: 1-1/8 inches wide by 4-5/8 inches long
• Black finish for consistent appearance in dark-frame and commercial door applications
• Heavy-duty construction suitable for frequent-use door cycles

Compatibility

Designed as an OEM-style replacement or new-installation invisible spring hinge for 1-3/4 inch thick doors requiring concealed hardware with automatic door return.

Installation Notes

Installation is typically performed by a finish carpenter or qualified door hardware installer. Precise mortise routing into both the door edge and the door frame is required — use a router and hinge mortise template sized for this hinge model to ensure proper fit and spring tension alignment. Verify door weight and door thickness before installation, as improper mortise depth will affect spring function and door closure. Follow applicable building code requirements for door hardware in the jurisdiction of installation.