To build a waggon wheel, clear a smooth place upon a floor, levelled with ant-hill clay, or preferably smooth planked. Take a ½in. straight-edged batten of rather more than 5ft. in length, and 3in. or 4in. in width; clench or screw a cross piece on this, so as to form a boss in the centre, as in the figure on next page; and through this, at the edge of the batten, bore a hole with a bradawl, which being also bored into the floor forms a pivot for it to work on. At 1in. from the centre, bore a hole, through which a pencil or a pointed scoring iron can be passed, to draw the first circle for the bore of the nave. At 4½in. bore another, to mark the circumference of the nave. If a front wheel is required, bore two holes at 15in. and 18in. for the inner and outer circumference of the felloes, or make them at 2ft. 2½in. and 2ft. 6in. for a hind wheel. Having drawn these circles, decide upon the number of spokes you intend to use, which will most likely be eight or ten for a fore wheel and twelve or fourteen for a hinder, such as is shown in our example (Fig. 1). Divide 360, the number of degrees in a circle, by the number of spokes, thus—360° divided by 8 is 45°; in like manner, 10 spokes would form angles of 36°, 12 of 30°, and 16 of 22½°. To obtain these angles, strike a circle on a good-sized sheet of writing or cartridge paper; fold it across the centre, exactly in half, open it and fold it in half the other way, taking care that the two parts of the previous fold perfectly coincide with each other; you will thus have angles of 90°, which may be called north, south, east, and west. Fold it again between every two of these, and you will obtain angles of 45°; these again divided will give angles of 22½°; and the next subdivision would give the thirty-two points of the compass, equal to 11¼° each. To obtain angles of 10°, divide each angle of 90° into three parts, and subdivide each of them into three. The strong lines in our next figure indicate angles of 22½° for a sixteen-spoke wheel, and the faint lines angles of 10°. Our diagram of the wheel was drawn with a bit of card cut to the exact size shown in our figure, pivoted on one pin, while the point of an HH pencil was passed through other pin-holes to draw the circumference. If two of these lines should come very close together, it will be seen that the pin-holes are not pierced in the same radial line, or they would break one into the other; but by placing them a little on either side concentric circles can be drawn as closely as requisite.
Now, cut a piece of thin board or stiff paper to the angle at which the spokes are to be set—in this instance 22½°—and with the aid of your straight-edge draw a line across, through the centre, to both sides of the circumference of your wheel; draw another across this at right angles, and test the lines by trying whether each quarter will contain four times the mould you have cut to the angle of 22½°; then draw two other lines of 45°, and subdivide each space into the required angles of 22½°.
Suppose your spokes are to be 1in. thick, withdraw the bradawl that has served you as a pivot, and bore two holes, each ½in. from the central line, and, pivoting the batten on each of these in succession, you will be able to draw the lines showing the thickness of your spokes, a, the original line still indicating the direction of their centre. Then divide the circumference of your felloe into eight segments of 45°, and draw short lines across it as at d ([p. 368]), to indicate the length of the felloe pieces, each of which must contain one pair of spokes, while its ends come fairly in the centre of the space between two others. Take a thin piece of board and cut a mould for the felloe pieces, marking on it the lines for the dowel holes, d, and those for the insertion of the spokes, c. Then in like manner cut a board with a circumference of 9in. as a mould for the nave, and on it draw the lines which mark the mortices for the insertion of the spokes, b. The nave should be turned of some good solid even-grained wood, not too hard; elm is well calculated for the purpose. It is generally 9in. or 10in. long, and it should have a hole 1in. in diameter through its centre. A narrow pit, 3ft. in depth, is dug, and two stout beams, 9in. apart, laid along its edges; a 1in. rod of iron is passed through the hole in the nave, which, with its iron bands already driven on, is placed between the beams, supported by the ends of the rod which rest upon them (stout trestles, 3ft. high, are sometimes used instead of the pit). In one of the beams at the back of the nave is a stout upright, with a line marked upon it as a guide in boring the holes truly.
Naves, to turn.
To turn a nave to the proper form without the assistance of a turning lathe, the following makeshift contrivance will be found useful and efficient. Fit up four strong planks, or a strong stool, of form shown in the accompanying illustration. Cut out two upright cheeks, which must be fitted by mortices to the upper surface of the stool. Then make a Ｔ rest, and fit it in the centre of the stool, in one of a train of square holes cut behind the line of the cheeks. The block of wood intended to form the nave must have an ordinary auger hole bored through its true centre, and in this must be firmly wedged an iron bar, with a crank or handle bent at one end; this bar rests on bearings prepared for it in the cheeks, one bearing is formed by boring a hole just large enough to let the plain end of the bar through, and the other by sawing out a deep notch for the handle end to drop into, when it is prevented from becoming displaced by a pin passed in above it. The man about to officiate as turner sits astride on the stool, presses a long-handled gouge or chisel by the action of his shoulder firmly down on the rest, with its cutting edge against the nave log, which is turned steadily round by an assistant who has charge of the handle; the whole operation being conducted much on the principle of tool grinding, only that the motion of the log is always towards the man who manages the chisel. The rest is advanced as the log decreases in diameter.
Wheels, to build.
If the wheel is to have what is called a dish, cut a small piece of wood ([Fig. 3, p. 368]) to the angle at which the spokes are to project forward; and, having marked off all the mortices, which will be ¾in. wide by 1½in. long, take a brace and ¾in. bit, or a ¾in. screw auger, and bore two holes in the space marked for each mortice, as in Fig. 2, taking care to centre most accurately the spot at which the point of your bit or auger is inserted, and to keep its true direction by the aid of the upright line and the small angled board. The mortices will then be finished with a ¾in. mortice chisel and mallet. The holes in the felloe (Fig. 4) will be bored at the same angle with a 1in. auger; for, as the spoke will be 1½in. from back to front, there will be shoulder enough in those directions without weakening it by cutting a shoulder on the sides. Of course, the shoulders, both at the felloe and at the nave, will be cut to the same angle at which the holes are bored. The tenon should be less than 3in. in length, so that it may allow of the subsequent boring of a 3in. hole in the nave to receive the bush or iron sheathing in which the axle turns; and in like manner the ends inserted in the felloes should be less than 3in. long, so that they may not receive any pressure from the tire. Fig. 5 shows the centreing of the felloe ends to bore the dowel holes. Now, resting the nave on its iron rod upon the beams of the pit or trestles, drive in the first spoke, testing it by the upright line and by your angled board. Then, boring a hole in your upright, drive in a peg and cut it off at such a length that the first spoke may just touch it in passing. Drive in all the other spokes so that they also touch the end of the peg, and then in the end of each spoke make a cut 1in. deep, with a fine tenon saw, to receive a wedge of hard wood when the wheel is built. Then in one end of each felloe drive a dowel (d) rather stiffly, but so that it does not bottom in the hole; leave half its length projecting. Take a screw clamp and compress two of the spokes together till their ends will enter the holes in one felloe piece; drive it about ¾ in. on, and slack off the clamp. If you have not a clamp, pass three or four turns of rope or thong round the two spokes, and twist them tightly with a hammer handle or other lever. Do the same with the next pair, and fit on the next felloe piece, taking care that it receives fairly the dowel of the first. Proceed in this manner all round, then look carefully to the fair insertion of all the spoke ends and dowels, and, being satisfied of this, keep the wheel turning slowly, and strike the felloe pieces homeward by smart blows of a mallet as each spoke passes you. When they are all fairly home, drive in the wedges to the spoke ends, trim off the felloe as neatly as you wish, insert the bush in the nave, and have the wheel tired in the manner described at pp. 195, 196.
