Part 10 (1/2)
[Ill.u.s.tration: Fig. 221.--Stop-bound Door.]
[Ill.u.s.tration: Fig. 222.--b.u.t.t Hinge.]
[Ill.u.s.tration: Fig. 223.--Gauging.]
[Ill.u.s.tration: Fig. 224.--Marking for Recess.]
[Ill.u.s.tration: Fig. 225.--Sawing for the Recess.]
ALIGNMENT.--Another fault that is fairly common is having the axes of the hinges out of alignment. Especially is this the case when three hinges are used to hang a wardrobe or other large door. It is absolutely necessary in all cases that the exact centres of the pivot-pins of the hinges should be in a straight line.
Particular attention to alignment is necessary when the body and the door frame are shaped on the face side. A familiar example that every reader may inspect for himself is the curved side of a railway carriage body and railway carriage door, where he will notice that a specially wide hinge has to be used at the bottom of the door to give the necessary alignment.
Hinges fixed on work with their centres out of truth are often overlooked by the inexperienced worker, and this is a frequent cause of creaking.
GAUGING.--Fig. 222 is a sketch of a bra.s.s b.u.t.t hinge, open. Fig. 223 ill.u.s.trates a similar hinge closed, and shows the gauge set so that the point of the marker is exactly to the centre of the pivot-pin. This distance we will call C. Now turn to Fig. 224. The distance C has been gauged from the face side of the frame. The gauge is then set to the thickness of the hinge at its thickest portion, and to prevent ”hinge-bind” see that the gauge is set on the _fine_ side. Remember that the tapered point of the steel spur or marking awl will part the fibres of the timber a little more than the fine point, and give you a wider gauge line than was antic.i.p.ated when you set the gauge. The inexperienced worker nearly always overlooks this. The result is a hinge-bound door, the cause of which is not discovered by the worker because he is so sure that he has set the gauge correctly. The distance B, Fig. 226, shows the line gauged for the thickness of the hinge.
POSITION OF HINGES.--Another difficulty to the beginner is the position for his hinges, and it may here be stated that the general rule is to carry a line across the face of the work from the inside of the cross rail and place the hinge at E, as Fig. 224.
[Ill.u.s.tration: Fig. 226.--Tool Operation when Paring Out the Hinge Recess in the Door.]
SAWING FOR THE RECESS.--After marking out for the hinge, as shown at Fig.
224, take a fine-toothed saw (a dovetail saw is considered the best) and saw down as shown at Fig. 225, care being taken not to cut beyond the gauge lines. In this sketch three intermediate saw kerfs are shown, but if the hinge is of great length, say 5 or 6 ins., the removal of the waste wood will be greatly facilitated by the addition of more intermediate saw kerfs. These cuts sever the cross fibres and allow the timber to be easily pared away in short lengths.
In Fig. 226 we see the tool operation when paring out the hinge recess.
At the left of the drawing the recess is shown marked. Take a 3/4 in.
chisel and, using it as a knife (see A), deepen the gauge lines. Then stab the chisel downwards, as at B, to deepen the end lines. Next, take the chisel and pare away the back of the recess as at C. The work may then be completed by paring neatly till the bottom of the recess is flat.
[Ill.u.s.tration: Fig. 227., Fig. 228. The Hingeing of a Box Lid.]
STOPPED HINGED JOINTS FOR BOX WORK.--Fig. 227 is a section through a small box similar to a lady's work-box (the back of the box in the ill.u.s.tration is enlarged in thickness to clearly show the position of the hinge). In this case the knuckle of the hinge is let into the woodwork until it is flush with the back of the box, and the gauge would have to be set to the total width of the hinge. The back edges of the lid and the back edge of the lower portion of the box are planed away at an angle of 45 degrees as indicated by the dotted lines.
Fig. 228 shows the same box with the lid open, and it will be observed that the chamfered edges come together and form a stop which prevents the lid falling backwards and breaking the box. This method of letting-in the knuckle flush is a useful one for box work because the ordinary stock bra.s.s b.u.t.t hinge can be used. Attention may, however, be called to the ”stopped b.u.t.t-hinge,” which is specially made to answer the above purpose; in its action a similar mechanical principle as the one applied to the box is used.
[Ill.u.s.tration: Fig. 229.--Strap Hinge.]
[Ill.u.s.tration: Fig. 230.--Reversible or Double-folding Screen Hinge.]
[Ill.u.s.tration: Fig. 231.--Pivot Hinge for Screens.]
[Ill.u.s.tration: Fig. 232.--Non-reversible Screen Hinge.]
TYPES OF HINGES.--Fig. 229 is an elongated variety of the b.u.t.t hinge, known in the trade as ”strap hinge,” ”desk hinge,” or ”bagatelle hinge.”
As its name indicates, it is used on folding bagatelle tables, small writing desks, and other types of work that have but a narrow margin on which to fix the hinges. The long, narrow plates are sunk flush into the wood, the knuckle or rounded portion projecting.
[Ill.u.s.tration: Fig. 233.--Back Flap Hinge.]
[Ill.u.s.tration: Fig. 234.--Card Table Hinge.]