Graphical Construction Glossary >> Doors. >> Door Hinges >> Piano Hinges

Piano Hinges

The name is taken from the type of hinge fitted to the lid that covers a piano keyboard. Any hinge that is continuous for the full length of the join. Also called Continuous Hinges.

Continuous Geared Hinge

An aluminium door hinge that is continuous for the full height of the door. Designed for heavy doors in high use conditions.

Piano Hinges : The first form of continuous hinge

The very first hinge of this type that I ever fixed was to a tool box that I made when I was about nineteen. The brass piano hinge was easy to fit, just cut to length and screw into position and yet it was very sturdy. It survived a few years of rough handling that would have wrecked the box if I had used just two or three butt hinges.

• Used in many places other than pianos, these hinges are sold in stock lengths and cut to the required size.
• Brass piano hinges are far more expensive than the type in the photo, but in this instance I do think that the extra expense is well worth it. Brass hinges in general are thicker than steel and have a lot greater stiffness.
• The hinge in the photo above was on a wardrobe door (the photo has been flipped sideways) in a hotel room that I stayed in. It is very thin metal, with a finish that is already getting rust marks showing through. This type of hinge is much loved by cabinetmakers because it is sold in rolls. Yep... that's right, when the hinge is laid open and flat it can be rolled up into a coil of maybe two feet diameter. Greater length means less wastage.

Continuous Geared Hinge : A sectional plan of a geared hinge. Image provided by Hafele Australia Pty. Ltd.

Now for something completely different. What you are looking at above is a drawing of a hinge that is designed for very hard work. In places like hospitals and hotel corridors where the doors are used incessantly for long periods and often hit by trolleys and wheeled carts or beds then these hinges come into their own.

• This type of hinge has been tested oner 1.5 million cycles, using a door 75kg weight. The maximum weight of door recommended is 125kg.
• The gearing action of the hinge makes heavy doors easier for elderly and disabled persons to use.
• What you see above is a face fixing hinge. They can also be part face and part edge fixed or both edge fixed, i.e. mortised.
• The mortise version takes more space so it is more often used in new installations , while a face fixed one can be retro-fitted to an existing door.
• Of note here is the fixing by machine screws and a through bolt. Ordinary screws can be used also, but this is an option where great strength is needed.

Continuous Hinges : A full mortise hinge Image provided by Hafele Australia Pty. Ltd.

Because of the large gap required by the hinge this one is used mainly on new work where the doors are made up to 8mm narrower to allow for this type of hinge.

Continuous Hinges : A Half Surface Hinge Image provided by Hafele Australia Pty. Ltd.

The half surface hinge is mainly used for upgrading work. In the photo you can see that the face leaf has a cover plate so that the screws are concealed.

Continuous Hinges : The gearing action Image provided by Hafele Australia Pty. Ltd.

At first glance you may have thought that these hinges only open 90 degrees. Not so. As you can see the centre cover moves also giving a full 180 degree opening angle.

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