NNSWERS TO QUERIES.
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Our readers will be infor ned by the Editor on any points connected with the construction or use of commercial motors. Where a direct reply is desired, a stany:ed addressed envelope should be enclosed : if a request for privacy is not specially made, any query and answer may be published-.
Locating Magneto Trouble.
[4355] (Strathdon).—There is nothing to indicate that the magneto is seriously at fault, otherwise it would not run the engine at all. . The magnets 'might have weakened a little, but not unless the magneto is over five years old. . Our experience in that in nine out of ten such cases, the starting trouble is due to faulty carburation. As regards the magneto,. it is only necessary to see that the platinums are set very close, and the same applies to the plug points, Do nut bind the wires to the plugs but keep them apart.
Board of Trade Regulations Regarding Compressed Gas.
[4356] (Bristol).—We have not before us the details of the Board of Trade regulations with regard to carrying gas under pressure. The reference we have made was dictated by our ordinary common knowledge of the existence of such regulations : for instance, cylinders that are required to contain compre.sseil. gas have to'be tested and approved by the Board of Trade, and certain requirements obviously
are laid down. We also believe that there are regulations with regard to screening cylinders from the sun, and there are regulations in connection with their carriage by rail. We can only suggest that you write to the Board of Trade for a copy of their regulations.
Should Springs be Tempered After Heating for Forging Purposes ?
[4357] (Co. Down).—Springs certainly require tempering after they. have been heated for forging or other similar purpose. The correct temperature for the process is 550 degrees Fahr. When this temperature is reached the steel; if brightened beforehand, will turn a dark purple in colour,. An alloy of 1 part tin to 12 parts lead melts at this temperature, and a pellet of this metal can be used to judge of the heat. You will be well advised, hOwever, to leave the job to an expert, as spring tempering is not at all work for amateuTs.
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Class A Men and the A.S.C., M.T.
[43§8.1 (South Molton).—Class A men are not accepted for service in the A.S.C. 154..T., unless possessed of special qualifications. We do not think that your capacity to drive will be of any account in that regard. In any case, you will have to apply through jourlocal recruiting authorities.
Wants Gas Cylinders.
[4359] (Welsh Agenth).—To run a 20 h.p. car 100 miles quite 1500 or 1600 cubic ft. of gas would be re quired. The only size of cylinder that you could expect to be able to buy would be one that had been taken from a railway coach by a railway. company which has discarded coal-gas for electric light. These. are generally used at 200 lb. pressure per sq. but you could not, on an ordinary vehicle, get enough cylinders at this pressure to take you the distance. The flexible container is a practical commercial proposition, and can be obtained from any of the concerns whose names are given in our issues. .When.feeding an-engine from a metal cylinder holding the,,gas under compression, that pressure has got • to be reduced either by taking the gas through a governor, or the gas may be taken into a small flexible holder, say, 15 cubic ft., through a reducing valve, so that the engine has a small volume of gas at atmo spheric pressure to draw upon. •
Operating a Lorry, for a Group of Farmers.
[4360] (Salop).—You will be Well advised to purchase a four-ton petrol lorry. Only a petrol vehicle would do the work which you require to be done in the time. In calculating your charges for this machine, you will find it best to base your prices on the total miles run, making the charges for loaded rune to cover the empty journeys. If, for this purpose, you obtain a return of. at least half-a-crown a mile you should be able to make it pay. If there is much waiting to be done you will have to take this into consideration when.calculating the cost. You should see a return of not less than 24 per day of service.