The Purchase Department.
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Street, London, S.W. As shown in the drawing there are no thumbscrews or springs utilized in its construction ; it is made out of the best quality dropforged steel. The jaws of the tool are so linked up that an instant grip is obtained on the pipe or other object being operated upon, and the more one pulls the greater is the hold exercised by the wrench.
Coating Metals, Wood and Earthenware with Lead.
We have had brought to our notice a new electrolytic process by which steel, iron, brass, copper and other metals may be economically coated with lead ; the thickness of the deposit can be varied from .001 to .125 in.
It is known as the Cowper Coles Process, and Lead. Ltd., 1 and 2, Old Pye Street, Westminster, has taken over the sole rights for commereially handling the system, suitable plant having been laid down in London.
The applications of the process are innumerable, fuel and water tanks, exposed pipe-lines, bolts and nuts, peal-plates, garage washing-trays, and even wooden footboaxds being but a few as applied to the motor inaustry. it is, of course, particularly useful for preventing corrosion and wastage in steel and iron work, and also for protecting the inside of piping from the action of corrosive chemicals.
Articles of earthenware, as well as wood, can be. coated with the utmost satisfaction. We understand that there is no reduction whatever in the tensile strength or ductility of metals when subjected to this particular process of coating. The lead is deposited rapidly and a remarkably smooth finish is always given to the work.
For an equal weight of metal it is cheaper than .hot galvanizing. An Extra Air-valve for Carburetters.
It is ''generally found necessary when using benzole and the heavier grades of petrol in engines, that
some means have to be devised to enable an extra quantity of air to be passed into the throttle or the air inlet pipe. At a time like the present, when so many users of commercial vehicles are turning their attention to the use of benzole or the heavier grades of spirit, a de vice which should be of particular interest is the " K.A.V. Keyhole" extra air-valve, which is being marketed by Brown Bros., Ltd., Great Eastern Street, E.C. A sample valve has been submitted to us, and upon examination there appeared nothing to get out of order, and it is quite a compact fitting.
The accompanying sketch shows the device in sec tion. As will be seen, the valve itself takes the form of a plug engaging with a conical seat, a con siderable length of guiding surface for the plug being allowed for by the outer cylindrical casing. A coil spring causes the valve to be in a closed position until acted upon by Bowden wire, a control fingerlever, of course, being fitted within easy reach of the driver. A series of air ports taking the form of a keyhole, are. cut into the outer casing and are sealed by the sliding piston ; the shape of these ports
allows for a very gradual regulation of air to be obtained. The device should, of course, be fitted as
near to the throttle valve as possible. This is readily accomplished by the tapered screw boss pro vided for the purpose.
The valve is quite suction-tight when closed, so that if at any time the lighter classes of fuel he used,
which do not call for extra air, the .original conditions with respect to the quantity of air being used are not interfered with.
The air valve should also be particularly useful when coasting down a long incline, as then it could be
opened and air allowed to circulate through the cylinders with advantage. It also allows for producing an air brake in the engine.
The valve, when in position, offers no obstruction whatever to the free passage of the intake gas.