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and one penny a line of ten words For anything else published, with an allowance for photographs.
Workshop lips and smart repairs; long and successful runs; interesting photographs ; all are suitable subjects. We will knock your letters into shape and will prepare sketches, where necessary, before Publication. The absence of a sketch does not disqualify for a Prize. When tolling, use one side of the paper only and mention your employer's name as a guarantee of hona 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, 745, Rosebery 7'en ire, London, E.G.
Annual Bonuses are given to the most successful contributor:.
A Washer for Valve Repairs.
[1098] J.D." (Glasgow) writes:" I recently
effected a repair to a broken valve spring in a very simple manner, and I think that you will be interested to hear how I did it. I was about eight miles from home, and the inlet-valve spring broke very near to the middle. I did not have a spare with me, and it looked as if the journey .would have to be finished on the ' dot and carry one system. I effected a repair, however, with the aid of two washers, one a in. and the other a g in. The ; in. washer was placed on top of the larger one, and both were slipped over the valve stem. I next placed the broken halves of the spring in position, and then pushed the valve stem down and inserted the cotter.
The big washer should be larger in diameter than the spring, and if it is not, a larger washer should be employed. The smaller washer on top simply acts as a stop to prevent the spring's working sideways and pushing through the hole in the washer. If the end of the broken spring begins to slip from position it can be easily secured with a couple of pieces of thin wire or a piece of string."
A Useful Centre Cleaner.
[1099] " (Finsbury) writes I am forward ing you particulars of a useful little tool which I noticed in the 'American Machinist a week or two ago. It struck me as being one of those handy little things which many mechanics are pleased to possess, and I am sure you will agree with me as to its usefulness. The tool is very handy for cleaning the centres of mandrils, turned spindles, and so on, when it is desired that they should run truly in lathe and other machine centres. The handle should be bored out in order to lighten the tool. A piece of rag should be gripped between the spring jaws ; these should be slotted, as shown in the sketch, with a very fine saw, to give the necessary spring for gripping the rag." A Useful Stud Tool.
The sender of the following communication has been awarded the Ws. prise this week.
MOO] " A.P." (Leeds) writes :—" Drivers will find the followinF stud tool useful. I send you a description of a in. tool—any other size may be made as desired—which is made up as follows. A piece of in. round tool steel about 5 in. long is turned down on the outside to the shape shown in the sketch. A hole, 11 in. long, is drilled at the tapered end and this is tapped out to the bottom, and a good clean thread made. The tapered end should then be screwed on the outside, and the stock-end squared to take a tap wrench. A 1 in. nut should then be chased out slightly taper in order to suit the screwed tapered end of the tool. This nut should not be screwed out to go more than halfway down the tapered thread. Two saw cuts should then be made across the screwed end, and these should go down to the bottom of the tapped hole. The tapered end should be tempered, but care should be taken that it is not made too hard or the jaws will break off.
"When this tool is used for drawing studs, the box should be screwed down on to the stud, and the nut on the outside tightened with a spanner. The tool thus obtains a firm grip on the stud, which can be removed with the aid of a tap wrench. When in use as a stud box, the nut should be slackened back until the box is down hard on the stud, and then the nut should be tightened and the tool used as an ordinary stud box.
"The tool can be used as a die nut when required. It should, however, be used on damaged threads with care, and plenty of oil should be used ; it should be run down only a little at a time until a standard nut goes on the stud easily. It can, of course, be made of any convenient length ; in some awkward positions, considerable length is advantageous." A Grit and Mud Trap.
[1101] "CT." (Fulham) writes :—"I have often experienced a great deal of trouble through grit and mud being taken up with the feed water when filling the boiler or tank of a steam wagon. Although the greatest precautions may be taken by inserting the rose of the feed-pipe in a pail, it is almost impossible
to prevent grit being sucked up, especially when supplies are being taken from rivers and streams by the roadside ; this is particularly so when water has to be taken up in the dark and the supply-pipe dropped into the stream from a bridge. The trouble is that small pieces of grit find their way into the clack-boxes and get trapped between the clack and the seating. The climax, however, is reached when a small piece of grit or stone gets firmly wedged between the rim of the clack and the wall of the, clackbox. This prevents any movement of the valve, either up or down, and the result is that the engine is put out of action until the obstruction is removed. This means, on occasion, that the steam in the boiler has to be blown out. The enclosed sketch [We have had this re-drawn.--En.] illustrates a device which I have found to overcome this trouble completely. It is made from steam fittings, and is joined up to the suction pipe, which is cut away at any.convenient place between the tank and the feed pump. On my own wagon, the suction pipe is in. in diameter, and the special fittings 4 in. in diameter. As will be seen from the sketch, the improvement consists of one tee-piece and three reducing sockets, together with a short piece of pipe and a draw-off cock. When full of water these fittings are too heavy to be suspended by the feed-pipe alone, and it is necessary to make a clip in order to take the weight, and this may be secured to some main part of the wagon. You will see that the water has to flow straight through the trap, and in doing so the grit falls down into the short length of pipe. When using dirty water a great deal of mud settles down, and it is advisable to open the draw-off cock at least once a day. If this is done the boiler works better, as well as the clackboxes and the injectors. Where watering places are doubtful, this is a necessary precaution,"
An Acid Repair.
1.1102j " W.F." (Acton) writes :—" I should like to bring to your notice a little dodge which has proved of the greatest assistance to me on several occasions. I have found, when replacing sliding pinions in a new gearbox, that they are sometimes a little tight on the sliding shaft. The usual method, when this is the case, is to grind the interior of the sliding pinion until it will fit on to the sliding shaft.. This is a tedious operation at best. Whenever this job Falls to my lot I obtain a flat iron plate and lay the pinion, which is to undergo the treatment, upon it. I then fill the interior with nitric acid, and this eats away the interior sufficiently to enable it to slide over the shaft. Of course the length of time occupied by the acid to do its work varies according to the amount of metal which is to be eaten away."
pas the " D. and M." page in our issue for 21st May, 009, we pithliehed a letter describing a similar method of treatment—ED.]
A Budget of Hints and Advice.
[11031 " W.B." (Twickenham) writes I am send
ing you a few particulars of workshop dodges and hints, which will, I hope, prove serviceable to your readers. When pouring babbitt-metal, a small piece of resin should be thrown into the melted metal before it is poured into the bearing. " One often has to fit a washer which is a little too thick, and it becomes necessary to file it down before it can be used. As washers are too thin, as a rule, to hold in the jaws of a vice, this is apt to be rather ark awkward job. The best way to overcome the difficulty is to bed the washer for half its thickness into a small block of wood, to hold the wood in the vice, arid then to file the washer down to the desired thickness.
"Whilst speaking of filing, it may be as well to mention that a piece of chalk rubbed over the face of the file when a finishing cut is being taken will help to give a good surface, free from scratches, to the work. This is due to the fact that small pieces of metal will not stick and scratch the work, for the chalk acts as a lubricant. Chalk should also be rubbed on the file when work is being run between centres or in the ja,wchuck for filing purposes.
"Many mechanics have a special piece of oil-stone which they have had by them for years, and of which they are quite fond. This should be placed in a piece of cloth after use, as this absorbs the lubricant, and gum is prevented from forming on the surface ; this gum clogs the pores of the stone and renders it inefficient for its work.
"It is very important, when making small cutting tools in the shop, that they should be carefully hardened. Unless a special furnace is used it is next door to impossible to do this work as it should be done. The fire is very unsatisfactory, as is also a Bunsen flame or a blowpipe flame. A very good way is to melt a pot of lead, ascertain and carefully regulate the temperature of the melted metal, and then to immerse the tool in the metal.
"If acetylene headlights be used on a van or wagon, the tube should always be nipped when the water is turned off. The flame should not be allowed to burn until all the gas is exhausted, as this very rapidly' clogs the boles in the burner."