About Door Hinges

Door hinges are those metal plates that allow a door to swing back and forth between the closed and the open position. This action allows easy access to the interior of a building, or once inside, the door hinges then allow interior doors to open and close with ease. When a door hinge is installed, a hinge plate is attached to both the door and the frame of the doorway to create the mechanism for the movement of the door. The key to the operation of a door hinge is the hinge pin, that long solid shaft that allows the door to pivot along the axis of the hinge pin. Without the hinge pin the door would be an immovable object.

Types

There are two basic types of door hinges, and each one can be applied to an exterior door. One type is the strap hinge, which allows the door to swing outwards and away from the building. These large hinges are applied to the face of the door, so the appearance of the hinge becomes important also. Often they are made from decorative wrought iron with the hinge pin being enclosed in a metal casing, so that it cannot be removed. Strap hinges are most common on barn doors and gates, but on occasion they can be applied to the front door of a residential home for an attractive, yet rustic look.
The more common type of door hinge is the butt hinge with a removable hinge pin. These are common on almost all interior doors and they can also be found on any exterior door that swings inward.

Function

The butt hinge is by far the most common type of hinge in use today. Characteristic of the butt hinge are two separate hinge plates held together by a sturdy and removable hinge pin. A hinge plate is attached both to the door itself and the door jamb or door frame that supports the weight of the door. When properly installed the two sections of each hinge line up in such a way that the hinge pin can be easily inserted, and when the hinge pins are in place, the door swings freely without interference.

Warning

For a door to open and close properly at least two pairs (three if the door is heavy) of hinges need to be applied so that they attach firmly to both the door and the frame. With exterior strap hinges there is some margin for error, but when one hangs an exterior door using butt hinges, the fitting, alignment and location of the hinges becomes critical. The door must fit snugly within the opening to prevent air leaks and drafts from entering the home. Often strips of insulation are added to the door frame to help prevent air leakage.

Expert Insight

Make sure your hinges are strong enough to support the weight of the door that you are about to hang. A hollow core interior will only require two pair of three-to-four-inch hinges, while a solid core exterior door will require three pair of heavy-duty four-inch hinges. And don't forget that the hinge plate has to be flush with with the surface of the door. The slot for the hinge plate can be made with a wood chisel and hammer or an electric router.

Considerations

When one hangs an interior door using three sets of hinges, the order of installation of each hinge becomes very critical for a neat and clean job. First lay out the location of each hinge on the edge of the door. If you are using three hinges place one hinge dead center along the vertical axis of the door's edge and then place the second hinge just a few inches away from the top and bottom of the door. After the location of each hinge is marked, you can separate the top hinge and apply one plate to the door and one plate to the door frame. After that is done then the other two hinges are attached to the door, but the remaining half of the hinges should remain free. Now go ahead and put the door in place, by lining up the two plates of the top hinge and then sliding the hinge pin into place after they are properly aligned. Most likely you will need an assistant for this process. Finally, slots can be made for the other two hinges on the door frame, and these hinges can then be directly attached to the door frame. The door should now swing freely.