After running off a wheel on a bar of iron to get the exact length it is necessary to know how much should be left to allow for the bending. No hard and fast rule can be given, as some brands of iron contract in bending more than others; but if lin. longer than the circumference is left, it will be sufficient. Having cut off the bar and bent the tyre, place the wheel to be tyred back uppermost on a tub or on the anvil, putting an iron rod through the centre of the stock and the hole in the anvil; traverse the sole with a measuring wheel, as Fig. 1, marking a joint on the wheel, starting from the normal point on the measuring wheel at A, and setting the dial hand to the point of starting after the wheel has been traversed. Then run round the inside of the bent iron, marking the dial point at the finish; this will give the approximate point for cutting off previous to upsetting and welding, which on an ordinary tyre generally take about 5/8 in. Bear in mind that the tyre when welded up must be smaller than the wheel, to contract it together when shrunk on; this varies according to the make and substance of the wheel, from 3/8in. for a Warner wheel up to l 1/4in. smaller for larger and heavy wheels. After the tyre is welded, run it round again; it can be easily seen by the dial hand how much smaller the tyre is than the wheel, bearing in mind that the part made hot in welding will shrink about 1/8in. in cooling; this must be carefully noticed in light work, otherwise, if the tyre is too tight, the spokes of the wheel will be crippled. Fig. 1 is the measuring wheel, ready for use; Fig. 2 is a side view of the handle of the measiu-ing wheel.

Fig. 2.

Measuring Wheel for Cart Wheels.