Swinging Door Hardware
In addition to sliding door hardware the next most common application for specialty door hardware is for swing doors. What differentiates specialty door hinges from standard door hinges is a thicker gauge of steel for heavy duty strength, increased weight capacity to bear very heavy and large doors, tighter tolerances, and a superior quality finish for greater longevity in harsh conditions.
Strap Hinge Basics
Strap hinges come in various thicknesses, usually 1/4”, 5/16”, 3/8”, or 1/2” for doors weighing between 400 lbs. ─ 5,000 lbs. or greater. The hinges can be mounted to the wall, or mounted directly to the frame. Jambs can consist of steel frame, hollow block, brick, concrete, or wood construction. (7’ – 24’ tall or higher and 50’ wide or wider). Standard strap hinges are used for manually-operated wood or metal doors that are surface mounted to wood, formed metal, or steel jamb frames.
Manual or Powered Operation
Heavy duty strap hinges are used for manually-operated or power-operated large swinging wood and metal doors, and also on small doors which have a high frequency of operation (constant daily use). Ball bearing and disc bearing hinges meet different loading needs. Common strap lengths are 18”, 24” and 36”, but strap hinges can be fabricated to very long lengths as shown in the photo.
Things to Consider
The strap hinges used on swinging doors must be selected using the following criteria:
- Frequency of use
- Pintle type and location
- Frame / jamb construction
- Door size (width, height, thickness, and weight )
What Type of Hinges Do I Need?
Disc Bearing and Ball Bearing Hinges are used on manually-operated doors. Frequency of use drives hinge selection between disc or ball bearing styles. Ball bearing hinges are the preferred choice in high usage applications (over 20 operations per day).
How About Hinge Back Plates?
Where Do I Use Center Hinges?
Slide-fold doors require center hinges. They should be sized the same as the strap hinges, and equal to the size used for the jamb hinge.
What Type of Pintle?
The style of pintle depends on the door jamb and mounting requirements. Hinge pintles can be removable, held in place with a cotter pin; or they can be non-removable, sealed in the hinge. The pintle can be offset from the hinge for mounting to an open frame, or set back on the face of a wall to allow open doors to clear the doorway. A butt-style pintle leaf can mount to the inside of the frame with the pintle pin located at the edge of the opening.
Hinge Mounting Styles
Strap hinges can be mounted in a variety of ways, either directly to a frame or surface mounted with and without offsets.
Strap Hinge with Half-Butt Jamb Section
This half-surface strap hinge with a butt style pintle leaf mounts directly to the inside of the frame for door clearance, as opposed to a surface mount hinge. The pintle pin is located at the edge of the opening.
Full Surface Mount Strap Hinge with Jamb Section
Full surface mount hinges can have pintles with or without offsets. The offset pintle can be mounted on the frame, or set back on the face of the wall to allow open doors to clear the doorway. Alternatively, the pintle without offset can be located at the edge of the opening for mounting on the frame.
Back plates are used when through-bolting strap hinges to a non-reinforced door (i.e., hollow metal) to distribute the force of the fasteners over a larger surface of the door. This prevents damage to the door and adds structural reinforcement. Standard back plate sizes match most hinge sizes at 18”, 20”, 24”, 30” and 36”.
Center Strap Hinges
Take a “Moment” to Calculate for the Proper Hinge
“Moment” refers to the measure of the turning force on an object such as a hinge. Calculating hinge moment is critical to the selection of properly sized hinges. Three measurements are required to calculate hinge moment in order to select the proper hinge, as well as the number of hinges required.
- Weight of door (expressed in pounds)
- Width of door (expressed in feet)
- Height of door (expressed in feet)
To calculate the moment on the hinge, multiply the weight of the door by the width of the door. Weight x Width = Moment After moment is determined, obtain the manufacturer’s recommendation, using the moment and door height, for the proper hinge and the number of hinges required.
1,500 lbs Weight x 4’ Width = 6,000 ft/lbs of Moment
Traditionally designed decorative hinges function in exactly the same manner as standard strap hinges, but provide an enhanced aesthetic for historic renovation or building in the traditional style. Custom designs, such as the curved hinges pictured below, can be created so the radius of the hinge matches the radius of the door.
Special Architectural Hinge Design
The renovation of this historic fire house, pictured to the right, used strap hinges mounted on the inside of the doors to allow them to swing in, as the building was originally designed. Special back plates, mounted on the exterior, duplicate the look of a strap hinge when the doors are closed. Design Note: Doors of this size and weight usually require three hinges; however, a reinforced metal frame and specially engineered hinges with back plates allowed the 600 lb. door leaves to operate smoothly with only two hinges each.