RUNNING, UPKEEP AND OVERHAUL.
Page 75
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Interesting Contributions from Maintenance Engineers, Drivers and Mechanics.
Improvement in Radiator .
Design.
ASUGGESTION sent us by " W.S.," of Maidstone, is one that we coueider well worth the attention of all connected with the production of commercial vehicles. Our correspondent points out that in the usual construction of radiators there is no allowance made for the expansion of that part which contains water. the side members being rigid, and not having any water la them, remain comparatively cold, whikt the tubes, or their equivalent, get hot and must necessarily expand. •
It would appear that much of the breahing away of the solder joint between tubes and their plates may be due to the fact that no provision has been made for the lengthwise expansion of the rubes. Our correspondent makes a very practical suggestion, which is -well worthy of consideration. To overcome the difficulty • " W,S." proposes that the sidc. members might be made hollow so that they could contain water which would raise their temperature to that o U. tubes so that all should expand together.
To prevent the water from having too path and So starving the tubes, he suggests that constricted openings should he provided for the water entering and leaving the side Members.
It may be said that the expansion of 'copper is slightly less than that of aluinil:iran, but the radiation of the side nieml)ers would be greater than that of the tuber, , oWing to the greater surface expoaod to the air, SO this, with a little experimenting in the Size of the aperturea loading to the side members should enable a radiator maker to produce al article in which the expansion of the tubea and the side members wonld be equal.
1)&ecting Cracks in Metal Surfaces.
TO detect fins cracks in metal
sullaces, or to gauge accurately to whet extent such cracks are present, in erdcr to allow adequate precautions to be takea to prevent their increase, " of Lincoln, suggests the following idea :—He has frequently edopted this • method, which, incidentally has been • found to give a more (',efinite result than that obtained uneer a powerful lens.
The surface upon which tho crack is suspectet: Jr present is first wiped with a ,J:an rag-, after which a liberal Sulmly of petroleum is applied to the surfna. The eetroleum is allowed to
ninia undisturbed for several minutes naen the surface, in order to allow a portion to enter the crack. The time allowed for the petroleum to enter will dipend, of course, upon the nature of the cracks, being less for pronounced cracks than it will be for
the finer fissures. When it is considered that an entry has been made, all traces of the petroleum should be wiped from the surface, which should then be covered with a fine, even 'layer of chalk.
The chalk will be found to dry quickly nail the portion of the petroleum that has catered the crack will exude, making a clear and definite mark in the chalk, which will indicate the extent of the crack. This method has been fouud most useful in the examination of the surfaces of engines which are inaccessible. .
A Tail Lamp for Aiding Reversing.
DIFFICULTY it often experienced when hacking at night time, owing to the usual red lamp not giving any useful light by which a driver can see where his vehicle is going. A correspondent, "JAL," of Butterknowle, Co. Durham, tells us that he has, in the course of his work, to travel along a sleeper track some 80 yards long, with a drop of 1 ft. 6 ins. on each side, consequently, he has to be very careful to keep to the track.
To meet these conditions he has made a special tail lamp in which the box portion containing the ruby glass can be made to slide up, thus allowing the burner to give a light in all directions. He tells us that he has never seen one like it, and suggests that it may be useful to other drivers.
The construction of the lamp is follows. The back plate has its edges turned over so as to form a slide in which the front part can move upwards when required. The front part is formed as shown and has a red glass in the larger panel and clear glass in the side panel. It can be arranged for use with either electric light or acetylene.
More About Stripped Axle Nuts.
wE have received the following
from "JM.J.S.," of Luton, who, although agreeing in the main with our correspondent, `H.J.0.," whose letter on the above subject appeared in our issue of December 11th, points out that the particular design to which " H.J.O." applied his suggestion was, unfortunately, an unsuitable one, as the flange which he proposed to use as a aafeguard is not integral with the hub.
The only way of making use of our correspondent's idea, so far as " can see, would be to cut down the
inner protection plate and provide a flange on the hub which would run in the inside guard piece. " The attached sketch will illustrate the meaning. The idea might possibly be applied to existing vehicles, hut would, of course, be best incorporated in the original design.
Easy Starting.
WE were of the opinion that all that could be said on this subject had been said, but we still get letters sug-gesting various methods by which the task can be made easier. The latest of these letters comes from Castleford, Yorks, where " GM." has to start a fivetonner every morning.
Each night when his lorry comes in after the day's work, he waits until rho engine has cooled down a little and then Pours about a teaspoonful of paraffin into each cylinder through the coraPression tap, thus preventing the piston from gumming up in the cylinder. He then wedges the clutch pedal in the "out" position and under these conditions ho appears to be able to get a fairly easy start each Morning.