S.O.S Continuous Hinges – What Is A Continuous Hinge, Why Do I Need It, and How Do I Read It?

Here we can help you figure out exactly what a continuous hinge is, why you need this type of door hinge, and how to read this door hardware’s diagrams.

Continuous hinges were hard to understand, to visualize in my head, and frankly most of the same generic information was given out and changed solely based on brand specification. I am here today to give you the basics on what a continuous hinge is, the different kinds, their benefits, and how to read those confusing diagrams that you are seeing plastered all over hardware sites.

If you’re like me, then you’ve come into the realm of hardware and home renovation without much knowledge besides the google-binging you did late night or what your handy friends have told you. Throughout my countless binges I did find one item that, despite a plethora of diagrams and pictures shown, still perplexed me.

The continuous hinge.

First off, let us get into what a continuous hinge is.

A continuous hinge in the most basic sense is a hinge that runs the whole length of the surface, instead of [typically] three select points evenly spaced. The two sides that make up the hinge join in the center in a teeth like fashion, to form one moving part that is evenly supportive and a tad more conspicuous. To install the door hinge, there are a series of holes drilled into each side of the hinge to allow for attachment to the surface with screws normally, and this is where you see some variations from store to store based on the hole-pattern and the size of these sides and holes. Generally, continuous hinges are made from architectural aluminum and anodized so that they can resist corrosion and maintain a more general wear and tear. Now continuous hinges are also notorious for being called “piano hinges”, which makes total sense based on their origin. The continuous hinge was originally developed to provide the hinge joint in piano lids, in which they had to be extremely durable and light weight to support a pianos lighter wood variables yet heavy angled pressure.

Now, for the different types of continuous hinges.

There are the basic piano hinges, which do not have any gears and are pretty straight forward, and then there are geared hinges, which can get much more complicated and serve a wider range of purposes. A geared continuous hinge is available in many different styles, including the following:

  • Concealed
  • Full Surface ( Standard and Mortise)
  • Half Surface (Standard and Mortise)
  • Swing Clear
  • and Toilet Partition

The swing clear and toilet partition are pretty much solely for new construction and more contemporary residential applications, so I won’t be delving much into those door hinges, but as for the concealed and surface hinges there is a lot to cover.


Continuous hinges are used in a wide range of commercial uses, such as schools, hospitals, offices, airports, stadiums, storefronts…you name it there is probably a continuous hinge in that commercial building you’re thinking of. Even smaller items like toolboxes and electrical doors feature continuous hinges, which you might not think of on an everyday basis.

What is the benefit of a continuous hinge though, you ask? Well let me tell you. The first benefit is that a continuous hinge can distribute a doors weight more evenly along the frame, so when you have a high traffic door or a very secure door (think a refrigerator door with a million condiments on the shelves) then your door will be sturdy and won’t sag over time. This is why these hinges are so attractive for commercial applications, because they are built to last and lightweight. The second benefit is that they are inconspicuous. These hinges are study yet so unobtrusive that they are often used for cabinetry (you can see examples of these hinges being used for inconspicuous cabinetry at our sister company Hanskrug.)The benefit of using this hardware for cabinetry doors is that they can close with an extremely small hinge gap and can open with a 180 degree radius (in one fluid motion I might add), all without spoiling the appearance of the cabinetry. So essentially what I am saying is they are aesthetically inconspicuous and functional. Thirdly, continuous hinges despite their diagrams are easy to install and align. Even though they are complex in their function, all it normally takes to install the hinges are some through bolts or machines screws and a little bit of elbow grease. They’re light weight, so it isn’t hard to carry around to the door or object that you are applying it to, and its relatively easy to match up to an old continuous hinge based on the templated hole pattern.

So as a recap, continuous hinges are built to last, aesthetically inconspicuous and functional, and they are easy to install and align. Who doesn’t want to get some bang for their buck?

Alas, the struggle that I faced and I’m sure some others did as well. HOW TO READ THOSE DIAGRAMS GIVEN. This took a bit more research and I’ve taken the time to draw out some simple ways to read and understand what those diagrams are saying.

Above is a diagram of one of our continuous hinges which is a full surface, limited frame mortise hinge, and we’re going to use an entry door as the example object for explaining this.

When looking at this diagram you need to picture it from an aerial view.

I know that title is a mouthful, but here is what it means. The hinge is a full surface hinge, which means that it runs along the side of the door and is visible and not along inner frame where the metal door frame touch, hiding the hinges. This hinge runs along the outside of the door.

As for the information provided on the side for this hinge, it is telling the customer that it is the full surface continuous hinge, saying where the hinge location is on the door (either the outside of the door or resting inside the door frame. The next bullet explains that it is for a limited frame application, which means that ———-. Next, it states that our continuous hinge has a tamper resistant cover, so that no average joe can come by and mess with your continuous door hinge. Essentially this is just saying we have given your hinge a bit of extra security. The clearance given between the door and frame is stated to be 1/32” of an inch, which is almost unseen, so it is saying that the door will not be flush with the frame, but that there was be an extremely small and almost unnoticeable gap. Lastly, the length description states that we have continuous hinges that are available for 83 inch doors and a heavy duty hinge available for 95 inch doors.

Now in this diagram you can see the gear function pretty clearly. This shows where the gear is located in the functionality of the continuous hinge. For our full surface hinges, this gear is either directly atop the door or on the inside of the door frame. Long story short, the mechanics that make the door physically open are either placed overtop the gap between the door and the frame, or located over the door frame and extends itself to where the door material is.

As for these measurements, let’s go from the bottom then move left to right. The very bottom measurement (1/32”) represents what is the “door to frame clearance”. This is the space between the door and the frame, with the hinge holding the two pieces together on the side.

Next, the middle measurement (1-7/16”) is the narrow fit frame application. What this stands for is the width from where this “side” of the gear starts to where the end of the hinge function is. You can see that it extends from one outer side of the door frame to where the continuous hinge ends. This essentially is the width that your door frame needs to be to function, but only 7/8” is necessary to securely mount your continuous hinge to the door frame.

On the far left we have two measurements. The first is called your projection frame leaf (19/32”) which tells you how far off the door frame the continuous hinge sits, or how far it projects from the frame. The second number is simply the projects to gear special difference (25/32”.) All this number tells you is the difference in measurement from the top of the projection frame leaf to the top of the continuous hinge at its highest point, which is the gear mechanics. This measurement is really just for reference and has no really important commercial application.

This part of the diagram dissection is going to be a tad tricky because I am going to group the two measurements together. Both measurements (25/32” and 1-5/32”) are where the visible hinges would sit IF we did not have the tamper proof cover. So this is what I would call the visible hinge inset, or in this case the tamper proof cover width. These measurements are the space allocated to place hardware to mount the continuous hinge to the door and frame. The left measurement (25/32”) is for the hardware for the door frame portion of the hinge, and the other (1-5/32”) is for the hardware to mount to the physical door. You can see the portion of the diagram that has the tamper proof cover illustrated.

As for the measurement in the very center, it’s probably exactly what you assumed. This measurement is the entire hinge length, which in this situation would be 3-3/16”. Pretty cut and dry.

Lastly, we have the measurement on the far right. Similar to the hinge measurement on the far left, this is also a door leaf projection (7/16”). Although shorter than the left-hand projection, this has the exact same function – to state how far out this section of the door hinge comes out (or projects) from the physical door. This measurement includes the tamper proof cover.


Hopefully this diagram dissection and insight on the benefits of a continuous hinge will leave you informed and confident to purchase! Feel free to check out our other continuous hinges at this link.

By | 2017-08-10T12:39:47+00:00 July 28th, 2017|Hardware Tips & Tricks|0 Comments

About the Author:

Hi! I am the web designer and marketing coordinator for Home Hardware Plus, a branch of Imperial USA

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