Cycle Repairing and Adjusting
With a Chapter on building a Bicycle from a Set of Parts

146 CYCLE REPAIRING truth part can be marked with chalk and knocked true on a hard-wood block with a mallet or copper hammer. This can be done cold with hub spindles, which are soft, but bracket spindles should be heated slightly before straightening, as they are much stiffer and hardened. To straighten, rest on pieces of brass across the vice jaws, and use a hammer with a piece of brass to protect the spindle from hammer marks. If the bearing parts of the bracket spindle are worn out of truth, they must be ground true on a suitable machine, or first softened, turned up true in the lathe, and re-hardened. Replacing Cup in Hub.—It should be explained that the manufacturers’ process of putting in cycle-hub cups is first to heat the hub case on a hot plate, press the cups in with a small screw press, fitting and bearing on the cup edges, and plunge in water to cool before removing the tool. Some makers press the cups in cold under a screw press ; this is quicker, but not so reliable. To replace a cup in an old hub, “ sweat ” it in with soft solder. To do this, thoroughly clean the hub and the outside of the cup till the surfaces are bright, tin the sur- faces with solder and killed spirits of salt, wipe off the superfluous solder whilst hot, press the cup in position, and heat up with the blowpipe till the solder is molten, and cool off at once with water. Great care is required, in applying the heat for soldering, to avoid letting down the temper of the cup. Fitting New Tube to Cycle.—It is necessary first to strip the frame of all fittings. Assuming that the top tube is to be replaced, file the side of the head lug and