Although many new patterns of hinges are now made, the butt hinge is still the most commonly used in furniture. It requires to be let flush into the wood, and the flaps can either be recessed equally into carcase and door, or the entire hingethickness can be cut into the door, depending upon the particular job. For instance, the recessing could be conveniently divided, whereas at C this would not be desirable as the door stands in from the carcase face, and it would look bad to cut right across the projection. The entire thickness is, therefore, cut in the door, though it is usual to let the free edge of the flap into the carcase to make it neater. This, however, does not affect pivoting; it is the knuckle position which counts.
Stages in letting butt hinge into door of a cupboard.
- butt hinge;
- hinge let equally into door and cupboard.
- hinge knuckle let entirely into door. Latter is slightly set back;
- sloping recess in cupboard side;
- recess in door edge;
- sizes of hinge to be noted;
- setting gauge to knuckle center;
- sawing recess;
- paring away the waste.
Fitting butt hinges.
To let in the hinge mark on the door edge the position, squaring the lines across in pencil. Assuming that the hingeing is to be set a gauge to the complete hinge thickness at the knuckle Y, Fig. 1 F, and mark the front face of the door between the pencil lines. Set a second gauge to the width up to the knuckle centre X and mark the edge. Saw the ends of the slot H, and complete the cut with the chisel. Screw on the hinge using two screws only, and, placing the door in position, transfer the marks to the cupboard. Reset the gauge to allow for the recessing of the door, and mark. When the door is flush the same setting of gauge is used. Slope away the wood at an angle, being careful not to remove any wood level with the knuckle. Fix with a single screw at each hinge and try. Carry out any adjustment before the remaining screws are inserted.
These butts can also be used for box lids, though special stop butts are sometimes employed, these opening through no more than 90 degrees. Strip hinges of the piano type are used for some work. They are simple to fit since only a continuous rebate has to be worked. The clock-case hinge has one flap wider than the other to allow for the projecting door.
For bureau falls the back-flap hinge with its wide flaps is used. It is also used for the leaves of some extending tables though a table with the rule joint needs the special hinge made for the purpose, this having one flap wider than the other so that it bridges across the hollow member of the moulding. The counter-sinking is also on the reverse side.
Reversible screen hinges.
The only point to note is that the distance between the centres must be not less than the thickness of the wood otherwise the folds will bind. If it is a little more it will not matter so far as the movement is concerned, but it will leave a gap which is a fault in a draught screen. They are let into the edges of the screen by a depth equal to exactly half the knuckle thickness. Butterfly hinges are intended to be screwed directly on to the face without being let in, and are therefore generally of a decorative character.
Sometimes, owing to some special feature of the work, it is impossible to use ordinary butts, and then the centre hinge is necessary. For instance, if ordinary butts were used for the left hand door the thickness would swing over and prevent the other door from opening. The cranked centre hinge brings the pivoting centre to the outer corner leaving the other door free to swing. Straight centre hinges are used when the centre is within the thickness of the wood. These are often used for heavy doors when there is a loose cornice. The centre is in line with the outer edge. It is imperative that the cornice is screwed on. Note that the cranked hinges are made in pairs, that intended for the bottom having a collar or washer so that the two plates have a slight clearance.
In addition, there are many hinges made for special purposes. The pivot hinge has the advantage that when the door is opened through 90 degrees the throw-off action has the effect of allowing the door to remain in line with the side of the cabinet. The slot which has to be cut in the door is 4.8mm wide and the hinge is designed for a door thickness of 22mm and a carcase thickness of 19mm.
Various arrangements can be made for the Onyx hinge. It is concealed at the outside, but a fitting is advisable beforehand. The advantage of the lift-off hinge is that the doors in adjacent carcases can be pivoted without fouling each other. Alternatively, a door can fold back through 270 degrees.