{"product_id":"national-marker-n350769-square-spring-door-hinge-3-5-in","title":"National Marker N350769 Square Spring Door Hinge 3.5 in","description":"\u003ch3\u003eProduct Description\u003c\/h3\u003e\n\u003cp\u003eThe NATIONAL MARKER N350769 is a 3.5-inch square spring door hinge finished in oil rubbed bronze, part of the V520 series. It is designed to control door closing speed in fire-rated and standard door assemblies across residential, commercial, industrial, and institutional applications. The hinge features adjustable tension so closing force and speed can be tuned to match door weight and traffic demands. Cold-rolled steel construction provides the structural integrity required for listed fire-rated openings. Licensed contractors and finish carpenters typically install this component as part of a complete door hardware package.\u003c\/p\u003e\n\u003cp\u003eThe N350769 fits standard hinge cutouts with square corners, making it a direct drop-in replacement in most door prep configurations. It is suited for interior and exterior doors in light commercial and residential settings where self-closing hardware is required by code or building specification. Its adjustable closing speed makes it appropriate for high-traffic corridors, stairwell doors, and unit-entry doors in multi-family or institutional facilities.\u003c\/p\u003e\n\u003ch4\u003eKey Features\u003c\/h4\u003e\n\u003cul\u003e\n  \u003cli\u003eAdjustable tension allows field-tuning of closing force to match door weight and use conditions\u003c\/li\u003e\n  \u003cli\u003eAdjustable closing speed for consistent, controlled door movement\u003c\/li\u003e\n  \u003cli\u003eListed for fire-rated door openings per applicable fire-door assembly requirements\u003c\/li\u003e\n  \u003cli\u003eFits standard hinge cutout with square corners for straightforward installation\u003c\/li\u003e\n  \u003cli\u003eCold-rolled steel construction for durability in high-use environments\u003c\/li\u003e\n  \u003cli\u003eOil rubbed bronze finish suitable for residential and commercial aesthetic requirements\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch4\u003eCompatibility\u003c\/h4\u003e\n\u003cp\u003eDesigned as an OEM-style replacement spring hinge for standard door preparations requiring a 3.5-inch square-corner hinge mortise in fire-rated and non-rated door assemblies.\u003c\/p\u003e\n\u003ch4\u003eInstallation Notes\u003c\/h4\u003e\n\u003cp\u003eInstallation is typically performed by a licensed finish carpenter, door hardware installer, or general contractor. Power down or disengage any electronic access control hardware before removing existing hinges. Verify that the door frame and door edge are prepped to accept a 3.5-inch square-corner mortise before installation. When used in fire-rated openings, confirm the complete door assembly — frame, door, hardware, and hinge — meets the listing requirements of the applicable fire-door standard.\u003c\/p\u003e\n\u003ch4\u003eTechnical Specifications\u003c\/h4\u003e\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003eHinge Size\u003c\/strong\u003e: 3.5 inches square\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eCorner Style\u003c\/strong\u003e: Square\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eFinish\u003c\/strong\u003e: Oil Rubbed Bronze\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eMaterial\u003c\/strong\u003e: Cold-Rolled Steel\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eFire Rating\u003c\/strong\u003e: Listed for fire-rated openings\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eClosing Speed\u003c\/strong\u003e: Adjustable\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eTension\u003c\/strong\u003e: Adjustable\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eWeight\u003c\/strong\u003e: 0.792 pounds\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eSeries\u003c\/strong\u003e: V520\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eSold As\u003c\/strong\u003e: Each\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch4\u003eStandard Information\u003c\/h4\u003e\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003eBrand\u003c\/strong\u003e: NATIONAL MARKER\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eManufacturer Part Number\u003c\/strong\u003e: N350769\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"NATIONAL MARKER","offers":[{"title":"Default Title","offer_id":51345319297330,"sku":"N350769","price":27.26,"currency_code":"USD","in_stock":false}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0270\/4519\/9983\/files\/310550663.jpg?v=1782054636","url":"https:\/\/voomisupply.com\/products\/national-marker-n350769-square-spring-door-hinge-3-5-in","provider":"Voomi Supply","version":"1.0","type":"link"}