Woodwork Joints: How They Are Set Out, How Made and Where Used. William Fairham Fairham

Woodwork Joints: How They Are Set Out, How Made and Where Used - William Fairham Fairham


Скачать книгу
63, and set out half the width of the wood on each side of the dotted centre line. Thus, suppose the wood (W) to be 2 ins. wide, then set 1 in. on each side of the centre line. Take a square as at Fig. 64, and with a sharp penknife blade score or cut a line all round each piece of timber.

      Next take up a marking gauge, and set the marking point to half the thickness of the wood. The distance may be measured, and its exactness tested, by pricking a small hole from each side of the wood with the marking gauge and carefully noting that the pricked holes coincide. The gauge mark is clearly shown in the various illustrations. Now, take a pencil and scribble or mark "waste" on the parts you intend to cut away. This will save trouble later on, especially if you are making several joints at once. Take your sharp penknife or marking knife blade, and cut fairly deeply into the marked line on the portion you are going to pare away.

      Fix the wood firmly in your vice, or against your cutting board or bench stop, as may be more convenient to you, and with a sharp chisel cut away the wood up to the marked line, as at Fig. 66. The channel in the sketch is exaggerated, so as to show the method clearly. The object of using a penknife or marking knife to mark your work, instead of using a pencil, will be obvious. Owing to the knife having scored about 1⁄16 in. deep across the fibres of the wood, the timber will come away cleanly when the chisel is used, as at Fig. 66. The small channel thus made will form a guide in which to start your tenon or dovetail saw; it prevents the saw cutting on the wrong side of the marked line and thus making the halving too wide.

      Sawing.—Lay the work on the cutting board as at Fig. 67; or, if you prefer, put the work in the vice. Carefully saw down the work until you just touch the gauge line. Do not press heavily with the saw; use it lightly; the weight of the back iron which is fixed on the saw will ensure the saw feeding into the work quite fast enough. If the saw is newly sharpened it will, in fact, be an advantage to slightly ease the weight of the saw from off the wood, owing to the keenness of its edge. If the halving is a very wide one, additional cuts may be sawn between the outside marks, and these will greatly facilitate the removal of the waste wood when paring it away. For sawing the joint reference may be made to the chapter on Dovetailing.

      Paring away the waste material with a chisel is the next step, and this is shown at Fig. 68. The work may be chiselled either in a vertical or a horizontal position. The horizontal position is the easiest for the amateur who has a vice or handscrew, because he may hold the work securely with a mechanical device and so avoid the unnecessary risk to his fingers.

      Take the chisel and cut away A, Fig. 68; now turn the chisel and cut away B; after which keep the chisel horizontal and cut off "the top of the hill," as it were, C. Repeat the three operations until you gradually pare the wood away exactly to the gauge line. When chiselling, if you find a tendency for the work to chip or crumble at the back edge owing to the forward pressure of the chisel, turn your wood round and begin to cut from the other edge, allowing the chisel to finish paring at the centre.

      Joints Other than a Right Angle.—If the halving joint is at an angle similar to the sketch shown at Fig. 69, great care will have to be exercised in the use of the chisel, owing to the change in the direction of the grain of the wood. The arrow marks in this sketch distinctly indicate the direction in which the chiselling must be done so as to give a smooth result. This change of direction for cutting also applies to the bottom of the halving joint.

      Cutting Joint at End of Timber (Fig. 70).—Should the halving joint be used at the end of a piece of wood, as at Fig. 30, the waste material may be roughly sawn away and the flat surface trimmed up with a chisel.

      To saw out this type of halving joint, proceed to work the shoulder line as already described; then place the piece of wood obliquely in the vice as shown (Fig. 70) and proceed to saw down the vertical line, carefully watching the gauge line to see that you saw on the waste side of the lines. Then turn the piece of timber with its opposite edge towards you, and again use the saw as illustrated. You will this time only have to watch the gauge mark on the edge of the wood, because the saw will readily follow in the saw kerf already made. Now place the wood vertically in the vice, and keeping the saw in a horizontal position, saw down to the shoulder line.

      Halving joints properly made and fitted should knock together with the weight of the clenched fist; the use of a heavy mallet or hammer will deface the work.

       Table of Contents

      A bridle joint is often defined as the reverse of a mortise and tenon, and is chiefly used in the carpentry and joinery trades. The name probably originated from the fact that it bears some resemblance to the manner in which a bit slips into the horse's mouth and is fastened to the bridle. There are fewer varieties of the bridle joint than of the halved or the mortise and tenon; and this being the case we may take the opportunity of giving a few detailed directions, with explanatory illustrations, on the setting out and the making.

      Fig. 72 shows a bridle joint in what is perhaps its simplest form, the separate pieces being given at the left and the completed joint at the right. A joint of this type may be applied in nearly all cases where a halved or a mortise and tenon joint could be used. Bridle joints have an advantage as regards appearance over the mortise and tenoned variety in cases such as Fig. 73, which shows an occasional table leg fitted to the circular


Скачать книгу