The most commonly known and most widely used hinge today is the butt hinge, used to hinge both internal and external doors, cupboard doors, and lids for box. They are produced in a variety of sizes and made from different materials such as plastic, mild steel, stainless steel, cast iron, and brass.
Though the simple principle of a pivoting flap is still used widely, the hinge has over the years been adapted and changed to meet different requirements and needs, so that today there are dozens of varieties on the market, having either a special movement, or just designed to look better in use.
Despite being a simple device, the fitting of the butt hinge can be a challenge, and cause many problems to the inexperienced, so understanding hinges and how they work is an important thing to learn. The mistake that many make is to overlook the fact that there are quite strict rules and procedures that must be followed when fitting, and the fact that hinges do much more than just enable the door to open and close. When correctly fitted, a door will close without rubbing up against the shoulder of the rebate, be parallel, and provide an appropriate gap and clearances between the door and frame, all of which are achieved by the correct fitting and setting of the hinges.
Some hinges have a very special movement, so much so that they do not even resemble conventional hinges. A good example of this is the concealed hinge, which is used on most modern furniture, such as bedroom, wardrobes and kitchen unit doors. One of the reasons why these type of units need special hinges is that the doors do not fit into the opening of the cupboard as a door would into a door frame, rather they are 'lay-on' doors, that is, they close onto the front of the cupboard, with the width of the doors only slightly narrower than the units themselves.
This design where all the doors and drawers line up neatly up to each other giving a better look to the furniture would present a problem for the conventional hinge, as the doors would would not open very far before being restricted by the adjoining door. The concealed hinge is specially designed for such applications, and this ingenious design allows the door to open without the outer edge of the door moving out beyond the edge of the cabinet, thus allowing the door to open without restrictions. There are a number of different types of the concealed hinge produced,the differences being the size, and the amount to which they allow the door to open. The sizes are relative to the size of hole that is required in the door to receive them, 26 mm and 35 mm, the smaller intended for light work, and the larger for heavier doors. The differences in the extent to which they open is between 95 and 165 degrees, and as their name suggests, the concealed hinge is invisible when the door is closed.
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