I get calls every week from clients who want to install pivot hardware to hang their doors (and sometimes other items like bookcases and even refrigerators). Using pivot hardware can serve several different criteria on a job site such as aesthetics or perhaps because a door is too heavy, tall or wide or maybe just because the owner is looking to do something different or less common than hinges.
In my experience there seems to be a general lack of understanding of the use and application of pivot hardware by many home owners, contractors and even architects. Most of the time this is where the knowledge of the hardware professional is indispensable and can help save money, aggravation and even delays on projects. But first we must define pivot hardware (or sometimes called pivot hinges).
There are two primary types of pivots used in commercial / residential construction
a. Offset Pivots
b. Center Hung Pivots
The selection of the proper pivot hardware for a given application can best start with asking a simple question.
The first question I most commonly ask is whether a door is single acting or double acting. A single acting door is one that swings open in one direction only. Typical single acting doors are classroom doors and bedroom doors. Double acting doors swing open in two directions. Typical double acting doors are seen in restaurants where the door to the kitchen can swing “in and out” so as to better allow people to move into and out of the kitchen with a try full of dinner plates.
We can easily eliminate offset or center hung pivot based on the answer to the above question. If a door is single acting, then both offset and center hung are still possible candidates. But if the door is double acting, then we can absolutely eliminate offset pivots. So lets move forward with a better definition of center hung pivots.
Center Hung pivots are unique and allow for a special set of design criteria for a doorway to be met. These pivots should be considered when a client wants the hardware to be concealed as much as possible or when a doorway is double acting. Center hung pivots are mortised into the bottom and top of the door generally centered in the door in relationship to the thickness and typically about 3/4″ from the pivoting edge of the door to the center of the pivoting axis. This makes the pivot hardware very nearly completely hidden when the door is closed.
Also because the axis of pivoting is in the center the door can be accommodated to double act if the application calls for it. A typical double acting door can been seen in a hospital room bathroom. The pivot hardware on these doors is center hung. Typically this bathroom door swing in but in the event of an accident (such as a patient collapsing) the nurse can, by disengaging a special strike plate, swing the door out into the room to allow access.
Center hung pivot hardware is available for doors less than 100 lbs. as heavy as up to 1,000 lbs., range from just over $100.00 to well over $1,000.00 dollars, are available is most sprayed and architectural plated finishes and made by many manufacturers such as Rixson, ABH, Ives and Dorma.
The following are a few considerations when specifying or using center hung pivots.
a. Center Hung pivots are not for use of fire rated doors
b. May violate the warranty of the door manufacturer
c. Typically require a radius edge to one or both stiles of the door.
d. Can be used on single or double acting doors but the way a door is machined depends on this.
Now moving onto offset pivots and back to our first question weather or not a door is single or double acting. Again if it is double acting then offset pivots are not an option. But if the door is single acting the then offset pivots are required.
Offset pivots can be specified for a number of reasons but the most common are weight of the door and the design criteria set forth by the owner. Offset pivots have a much higher weight capacity than hinges and can be considered the best possible means of hanging a door. Because the weight of the door is born exclusively on the bottom arm of the pivot (which is directly connected to the pivot spindle) the weight of the door itself is carried by the floor (and ultimately the remainder of the building).
Offset pivots are visible at the top and bottom of the door and are generally only slightly more difficult to machine in doors than center hung pivots.
Offset pivots are named such because the vertical pivoting axis is “offset” from the face of the door. There are two common offsets, 3/4″ and 1 1/2″. 3/4″ is by far the most common. This means the distance from the face of the door to the pivoting axis is 3/4″. 1 1/2″ offset is also not uncommon but are generally only used when the the doorway requires a greater offset such as thicker than standard casing or when a door is set deeper into a jamb than normal.
Typical applications for offset pivots are wardrobe closets or lead lined doors in hospitals and clinics. And like its cousin center hung pivots, offset pivot hardware made made for doors as light as less than 100 lbs. as heavy as up to 1,500 lbs., range from just under $200.00 to well over $1,000.00 dollars, are available is most sprayed and architectural plated finishes and made by many manufacturers such as Rixson, ABH, Ives and Dorma.
The following are a few considerations when specifying or using offset pivots.
a. Offset pivots can be used on fire rated doors
b. Intermediate pivots can be specified so as to not violate the warranty of the door manufacturer
c. Do not require a radius edge to either stile of the door.
d. Can be costly depending on the size and weight of the door they are installed onto.
I enjoy talking about pivots, their general and less common uses and helping people determine the right pivot for their application.