Contributions from Drivers and Mechanics.
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TEN SHILLINGS WEEKLY for the Best Communication Received, and One Penny a Line of ten words for any thing else published.
Drivers of commercial-motor vehic.es and tractors, and mechanics and foremen (1 garages or shops, are invited to semi sluwt co • tributions on any subject winch is likely to prove of interest to our readers. Work. sh,p lips and smart repairs ; long and successful runs, interesting
Photographs : all are suitable subjects. Send a post-card, or a. letter, or a sketch to us—no matter how short, or how written, or how worded.
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I will "knock it into shape" and prepare sketches, where necessary, before publication. The absence of a sketch does nut disqualify for a prite. When writing use one side of the Pater only and mention your employer's name as a guarantte of bona fides. Neither your own nor your employer's name will be disclosed. Payment will be made immediately after publication. Address your letters to The Editor, THE COMMERCIAL MOTOR, 7-15, Rosebery Avenue, London, E.C.
A Compact Tool for Withdrawing Tight Bushes.
The sender of the following communication has been awarded the 10s. prize this week.
[706] " W.J.11." (Walthamstow) writes :—" From time to time I have seen, in the drivers' and mechanics' columns of your journal, descriptions of specially-made tools which :are designed to withdraw tight bushes. Most of these are more or less elaborate, and consist of little toggle arms, with many joints, which are liable to gel slack and, which are, in niy opinion, a general nuisance all round, The little tool I use has no toggle gear, as may be seen by the sketch, which I shall be glad if you will redraw. I made it. from a 1 in. bolt, One end was knocked up, in order to form a lip, whose action will readily he understood by a careful inspection of the sketch below. The bolt is split down the greater part of its length by a wedge-shaped cavity, and into this a small steel wedge is inserted, which may be pushed up into position by means .of a drift, which passes through a small round hole to the outer end of the tool. The principle of operation is to push the lipped end of the bolt through the hole in the bush (it will spring in sufficiently to allow this to be done),
and when it has passed through the hole, the lips will spring out and catch on the inner end of the bush. The wedge must then be driven up fairly tight, so as to hold the lips in position ; there is no need to force it. The application of a nut, and any suitable form of collar or packing, will readily force out the most obstinate of bushes: I think you will agree that this is a much-morecompact arrangement than many of the other schemes which I have already mentioned. It will, of course, be understood that, as the bush is pulled out, more packing should he inserted behind the nut." The Care of Driving Chains.
[707] " (Sandbach) writes :—" I have not recently seen in your columns many tips with regard to the 'care of driving chains, although sonic while back you had a. number of very-interesting communications on the subject of ' joining a. broken chain.' " The severe conditions, under which most driving chains on motor vehicles are used, makes it necessary that they should receive great care and attention in order that they may have a reasonably-long life. Unfortunately, many drivers, in my opinion, consider that, as the chain appears to be a robust sort of component, it needs only the very slightest of attention. Many drivers neglect this part of the vehicle entirely I am afraid, and hence complaints are frequent that chains are short-lived. It is quite evident that, as driving chains are composed of a large number of carefully-made small parts, there must be a number of little bearing surfaces, all of which require lubrication in their own small way. It is often difficult to insure that these parts shall be properly lubricated, unless a certain amount of trouble is taken in the matter. Once a chain is allowed thoroughly to run dry, lasting damage of a serious nature is often caused, owing to the fact that the hardened surfaces gall. When the smooth faces of the rollers and pins are destroyed, trouble soon follows, and it is extremely difficult to get a chain to run well when this state of affairs has been allowed to occur. Chains should always be overhauled at least fortnightly, and by overhauled I mean properly cleaned and mbricated. All the dirt and mud should be carefully taken off with a good stiff brush after the chains have been removed from the sprockets. The whole thing can then be usefully put into a trough of paraffin or turpentine and allowed to soak for two or three hours. This method effectually removes all dust and grit from the inner surfaces, which are ungetatable with a brush. A subsequent bath in boiling oil, or tallow and graphite, allows a nice film of this lubricant to percolate into the inner surfaces of the whole chain. Another factor which does much to render the life of many a good chain a short one is that a large number of drivers has no idea as to what is the correct tension at which to run a chain. Some like to run them very tight, as they are under the impression that, unless this be done, there is a danger of the chain jumping the teeth. They forget that a tight chain plays old Harry ' with the hearings as well as with the chain. In my opinion, the right tension for a driving chain is that which would be considered just too slack for a belt drive. I hope t hese few hints will prove useful" A Tank Trouble and Its Cure.
[708] " S.O.B." (Regent's Park) writes:—" The following account of how I helped a driver out of what looked like a serious mishap may prove of interest to some others of your readers.
" 1, myself, was driving a car of a well-known make at the time the trouble occurred; I used to put my machine up, with eight or ten others, at a garage run by a motor company in London. Going to tho garage one morning, another driver, whose car was in the next hay to mine, called me in to have a look at his petrol tank, which was leaking from the bottom, quite away from any seam or joint. This looked peculiar, as there was no sign of a knock or anything that would cause such a leak. Whilst was scraping the paint away from the leaky spotin order to make a better examination, the screwdriver with which I was scraping, went right through the bottom of the tank as if the latter had been an egg-shell. This was rather startling, the more so as the car in question was to start that morning for a long tour. However, something had to be done with it, and pretty quick, too! We caught most of the petrol that was running away, and thou lowered a small inspection lamp through the filling Jude, to enable us to see if there was anything inside the tank to cause such a leak. One look sufficed to show us the cause of it al!. This was nothing more nor less than about a teaspoonful of water, which had got into the tank somehow, had collected at the lowest point and had rusted
the metal completely through. This had happened in spite of the tank's having a heavy coat of tin inside—the tank was a steel one.
" Now for the repair. We had almost given it up for a bad job, as a patch soldered on was out of the question ; on this particular make of car, a very-considerable air pressure was carried (50 lb. to 60 lb.). A sweated or screw-held. patch would have been very difficult to make tight, considering that it would have had to have been done, there and then, on the car. At last a. bright, idea struck me, and I had the job fixed up in ten minutes. This is how I did it. I got hold of a tire security bolt, trimmed away the canvas, and then bent the mushroom part as near as possible to the radius of the tank, which was a circular one. I next went to a stationer's shop and obtained a good big piece of indiarubber, through the middle of which I cut a hole just large enough to press over the threaded part of the security bolt and so close up to the mushroom. I then mameuvred the bolt with the rubber on it through the filling hole of the tank and placed it with the stalk of the bolt projecting through the hole made by the screwdriver. A stout washer on the outside and the wing-nut screwed up tightly made as good a job of it as could be expected under the circumstances."
An Exhaust-pressure Turbine.
1709] " EN." (Plaistow) writes :—"I am a reader of the C.M.,' and I take a special interest in the drivers' pages. From time to time. I have read notices in your journal with regard to the lighting of motorbuses. I am not a driver myself, but I have often remarked the amount of pressure that appears to be wasted from the ordinary exhaust pipe. Could not a machine be devised, on the principle of the turbine, to be worked by this exhaust pressure? This turbine should he coupled to a small dynamo, whose electrical output could be used for light
ing the bus. I should like to know what your readers think of this suggestion."
[Our correspondent's suggestion is not a new one. Several attempts have been made to utilize the exhaust pressure in this way. No practicable results have accrued, owing to the fact that the exhaust pressure is too low, say 40 lb., to be of much use as a source of power_ If the free escape of the exhaust be restricted to any serious extent, the resulting back pressure acts detrimentally to the engine. A choked exhaust box, it should be remembered, will quickly cause an engine to run badly. The exhaust from a steam-engine, of the type that has been used on various models of steam cars, has been employed to propel the cooling fan. In this case, however, the exhaust pressure was much higher.—En.]
A Lathe Adaptation.
L710.1 " E.W." (Bedford) writes :—" I am enclosing a photograph which shows a useful alteration which I have carried out to an ordinary lathe that I have in my workshop. I made this into a screw cutter in a way which may be of interest to many of your readers. I fixed an eight-tooth cycle sprocket on the shaft at the end of the fixed headstock, and I then fixed up a. light shaft in front of the lathe from this point past the slide-rest. I drove this new shaft, by means of a cycle chain, from the sprocket I have already mentioned to another one which I fixed on the shaft. I had several pairs of old gearwheels by me, varying from 12 to 38 teeth, and, of these, I arranged a suitable pair to drive from the new shaft back on to the feeding screw of the slide rest. By altering the pairs of gear wheels, I was able, of course, to get almost any ratio for screw cutting which I wanted. The difficulty of bringing in the centre of the new extra shaft towards the slide-rest is easily overcome by altering the number of links in the cycle chain at the other end. I made the chain in about six pieces, and put it together with bolts, so as to be easily detachable. It may interest you to know that I have taken TECE COMMERCIAL Melton. from the first copy, and I am very fond of the 'Drivers and Mechanics" pages of your journal."