HIGHROAD & BY-ROAD.

Waikato Times, Volume 106, Issue 17804, 31 August 1929, Page 24 (Supplement)

HIGHROAD & BY-ROAD.

MOTOR CAR BUILDING

SILENCE MAKES BIG ADVANCE. « Periodically an “oldest model" of one of to-day's Letter known motorears is discovered, such as the 190* Oakland and 1903 Cadillac that were recently found still in service. Aside from the radical changes in appearance these earlier models serve to emphasise what strides automotive engineers have made in mechanical developments. One of the most- important contrasts is the “silencer" that has been built into the modern motorcar.

Discussing the roar and clatter of the early models a well-known General Motors distributor says they had either poorly designed mufflers or none at all; gears whined, and body and running gears protested loudly against the slightest road jolt. Large, clumsy valves contributed perhaps the greatest of all noises, for they, continued as long as the motor was in operation. Tlie silence of operation in to-day's cars is due largely to the development of precision instruments. Precision brought silent piston operation, smooth operative camshafts and noiseless opening and closing of valves. The ignition distributor strikingly illustrates what is involved in precision methods. It is estimated that with a six-cylinder engine making 3000 revolutions a minute the contacts on a six-lobe distributor are opened and closed 150 times a second, remaining each time on contact for approximately four one-thousandths of a second. The length of contact is even shorter at higher speed of operation.

THE INNER TUBE. In tube construction different compounds are used for different tubes. The tube must be air-tight and of course sturdy enough to hold the compressed air. The casing, no matter how strongly it is built, is merely a flat tyre once the tube has gone wrong. Through wash rods and driers and mill room and compounding processes, the rubber destined for tubes follows the same general route though using different compounds from the rubber destined for casings. But thereafter their paths separate. The tube rubber emerges from the calenders— i.c. mill consisting of three perfectly smooth rollers arranged vertically, sheeted out to given gauges and widths, is cut to lengths corresponding, to the circumference of the tube it is to become, rolled up sidewise on pipe-like cylinders called mandrels, loaded on racks and sent in to the vulcanising room to be cured.

When they emerge the tubes are peeled off the mandrels by compressed air, turning them wrong side out as neatly as milady takes off her gloxes. Then' they start their ride on the conveyors.

In different stages along the conveyor line a hole is punched in and the valve inserted, the tube ends arc brought together and securely cemented, the tube is partially inflated and carried through a water tank to make certain there are no leaks or air holes. From there it goes to final inspection.—Goodyear News.

DRIVE TO THE LEFT.

CUSTOM IN ENGLAND. The present custom in England of driving on the left side of the road may be traced back to antiquity. In the olden days, when horses were ridden and spears were used, it was vitally important that the real or potential enemy be on the right. To the left hand fell the duty of guiding (he mount; the thrust of the spear and the backward sweep of the sword could only be accomplished by the knight who was right-hand mounted.

TIGHTENING WIRE WHEELS

The most popular form of wire wheel in use at the present time is held to the hub by several helmet nuts disposed at equal intervals about the hub, centre. It is unwise to tighten any t>ps of wheel when it is resting on the ground, but this applies most particularly to the wire wheel, for in most cases the faces of the nuts are tapered and fit into similarly tapered female chambers on the edges of the stud holes. When these helmet nuts are lightened evenly the hub will centre itself, but if the wheel is resting on the ground it may not be able to do this.

A TROUBLE LIGHT SOCKET. On the switch boards of many English cars are to be seen two holes close together. For the benefit of the uninitiated, these holes are designed to take the two pins of a trouble light plug. This tip may save some owners from the trouble of wiring up a special trouble light socket. Incidentally, if a plug to fit these two holes is unavailable, do not forget that two pins of suitable size fastened directly to the two wires of the flexible lead will serve the purpose quite as well, although perhaps not so neatly.

CLOSED CAR WINDOWS. Stiff operation of the closed car windows may sometimes be experienced. This apparently mysterious trouble—for one would expect the windows to become freer in service, not tighter—frequently is due to damp swelling the felt runners in which the window edges slide. Of course, under the influence of dry weather, the trouble can be expected "to remedy itself, but in the meantime relief may be obtained by inserting a little grease or soft soap in the runners. DISCOVERY OF VULCANISATION.

MADE AUTO TYRES POSSIBLE. Vulcanisation Erst made possible the manufacture of rubber lyres and on this account, it. is interesting to know .just how this process was discovered. Charles Goodyear spent, many years in experimenting with gum trying to discover a method of treating it #*o that it would not sliffen with cold and melt, with heat, lie was only partially successful, however, unlit ls.'tf) when, while it a I king and demonstrating to some friends in the kitchen of Ids home, lie dropped a piece of rubber mixed with sulphur on the stove. It charred like leather. This was the discovery of vulcanisation.