Contributions from Drivers and Mechanics.
Page 20
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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 comniercial-motor vehic es and Ira. tors, and mechanics and foremen of garages or shops, are invited to send short cwaributions on any subject which is likely to Prove of interest to our readers. IVt,rkshop tips allit smart repairs ; lonA, and successful runs ; interesting photographs : all are suitable subjects. Send a post-card, or a letter, or a sketch to us—no inatLr hlw short, or how written, or ht.w worded. We will " knock it into shape" and preparesketches, where necessary, before publication. The absence of a sketch des 'tot disqualify for a prize. When writing use one side of the paper only and mention your emPloyer's name as a guitrantfe of bona fides. Neither your own nor your employer's name wilt be disclosed. Payment will be made immediately after publication. Address your letters to The Editor, THE Comvi-IRCIAL MOTOR, 7-15, Mosebery Avenue, London, E.C.
Slipping Clutches.
[929] " G.H." (Bootle) writes :—" I have found that a. great many leather-faced clutches give trouble owing to their fierceness, after they have become worn a little bit, because of the burr which forms on the leather. This of course, could be cured quite easily by taking the burr off with a rough file. The leather should then be dressed carefully with castor oil or some other suitable dressing. In very bad eases, it is best to have such clutches skimmed up in the lathe, care, of course, being taken that the rivets are well sunk into the leather. If the clutch has given trouble by slipping, it is quite likely to be cured by the filing away of the burr, but if it still gives trouble after that., the clutch spring should be adjusted. Care should be taken never to run with a slipping clutch, as the leather is soon totally ruined by so doing."
Marking Off Holes in Inaccessible Positions.
[9:30] " W.E.F." (Gainsborough) When erecting motor chassis, it is often necessary to mark off for the fixing of various brackets on the inside of the channel-steel or pressed-steel frame. It is fre quently a very difficult matter to drill such holes without marking them off on the other side of the channel. Your readers will know that this is always an awkward job, and one which takes up a lot of time. I now keep in my tool-box a small set of templates, which enables me to do jobs like this with ease. Each template consists of a small piece of sheet iron, which is bent over double, and has a hole drilled right through the two parts. The series of templates has a. range of standard size drilled holes. It will then be seen that a suitable one may be slipped over the flange where the hole has already been marked off, and the exact location of which may then be transferred to the other side of the channel, when drilling may be proceeded with quite easily."
[We described A somewhat similar arrangement to this in letter No. 815, which was published in our issue for the 12th January thin year. Our Gainshorough correspondent, however, evidently uses a set of these templates as a reglihir thing. Our previous correspondent had made a special jig for a job which was of a somewhat similar nature—an., W—h—en Turning Piston Rings.
The sender of the following communication has been awarded the Ws. prize this week.
[9:31] "II.B." (Sandie-16i) writes I send you herewith particulars of a piston-ring jig which I have. designed, and I submit the same for competition in your D. and M.' columns. This jig is especially useful when it is required to put through batches of, say, three or four dozen rings at one time. The sketch which I enclose [We have had this redrawn.— En. will probably illustrate the arrangement that I adopted quite well. I use two cylinders, one of which is to enclose a batch of rings ; the other is intended to be pushed inside the rings at the same time. The sketch shows a number of rings in position ready for turning. Two cast-iron end plates, which are used to clamp the rings together, are also shown. These are pulled tip tightly by means of the bolt which passes through the centre arrangement. One plate is made of extra thickness, in order that it may be held firmly in the lathe chuck. The larger cylinder is bored internally to suit the piston rings, while the smaller cylinder is turned externally to suit the inside diameter rings. The rings themselves are first roughly turned from the solid cylinder, as is the usual practice. They are then parted off and cut, and after this they are sprung into the large cylinder, care being taken to keep the points where they are sawn all in the same straight line. When the rings are thus put correctly into position, the smaller cylinder is slipped inside them. The end plates are then screwed tightly into place. It will be noticed that these last are grooved, in order to register with the inner cylinder correctly. When the whole is thus rigidly fixed in position, the outer cylinder is drawn off the rings, by means of several slots, which should be cut into it for this purpose. All is now ready for turning to the required diameter, and it will be seen that a running cut can be taken for the full length of the gang of rings. Of course the arrangement must not be chueked concentrically, but must be thrown slowly out of centre, in order to give the piston rings the necessary eccentricity. They, of course, as your readers will know, have to be fixed opposite the place at which they have been cut. The actual shane of the piston rings is not of moment in this description. I only set out to tell you of a method which I have, used for holding them."