For DRIVERS MECHANICS & FOREMEN.
Page 23
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A PRIZE OF TEN SliILLIIVOS is awarded each week to the render of the lest letter which we publish on this page: all others are paid for at the rate of a penny a line, with an allowance for photographs. All notes are edited before being published. MentiOn your employer's name, in confidence, as evidence of goad faith. Address, D., M. and IP„ "The Commercial Motor," 7-15, Bosebery Avenue, London, E.G. 1.
Lamps Alight.
On Satupday, Sept,einber 13th, Iight.your lamps at
i 8.20 in London, 8.37 in Edinburgh, 8.29 n Newcastle, 8.33 in Liverpool, 8.28 in Birmingham, 8.30 in Bristol, and 8.46 in Dublin.
A Novel Cylinder Grinding Rig.
The sender of the following communication has been -awarded the 'Ws. prize this week.
[2,011] " L.K.I." (Weymouth) writes :—" We had some interesting experiences recently in connection with a broken cylinder. First of all we welded it, using ti,b oxy-acetylene process, and before we finished the job we learned something abeut welding. For example, we discovered that, using a No. 1 pipe, it is not advisable to exceed 15 lb. pressm•e to the square inch. Secondly, when welding cast iron, the best welding material to use is mild steel rod, with borax as a .flux. Further, when using the oxy-acetylene process, it is inadvisable to;go over the same gretind twice: if you do, the metal becomes crystallized. Ultimately, we made a successful job, of,the weld, and erected the cylinder in place, but there we struck fresh trouble. We could get no compression in that cylinder. We therefore took it down; again, and discovered that it was no less than 1-32nd of an inch oval.
"We tried all over the town to find someone with a cylinder grinding machine, so that we could have it ground out, but without success. Then we put5it in the lathe, and tried to bore it, still 'unsuccessfully ; the metal was too hard.. Evidently we should have td try our hand at grinding it. The following description, and the attached sketch–:(Which we hay° had re-clzawn.—Fn.)—will, I am sure, be of service to some of your readers, who may find themselves similarly Paced. "We had in the shop a substantial pedestal drill, fitted with a rising and falling quill. We fitted a small emery wheel on to a special spindle, and fixed it in the self-centring chuck. The cylinder was firmly secured toothe revolving drill table. In view of the fact that grinding needs high cutting speeds, we set the drive of the drill to its highest ratio, and then met trouble owing to excessive vibration. This, however, we got over in a, very simple manner by bolting a weight to the pulley of the bottom countershaft. With a fine feed and care, we were able to make a really sound job, of this regrinding, and the motor is now as satisfactory as when new."
Improving a " Surplus " Lorry.
[2,012.1 " A.E.K." (Derby) writes:—" There are a good many lorries and vans that have been doing their bit.during the last five years, and are now home again and getting into the hands of all classes of commercial users. Naturally, some of these cars show defects and weaknesses de to the somewhat. arduous conditions under which theyhave been working, .and, in my opinion, a sure test of the efficiency of any.commercial motor is the degree of quietness with which it operates. Noise in a car is generally sufficient evidence that it has had a good deal of wear and tear. This state of disrepair is not necessarily confined to the engine and transmission. In fact, quite a lot may be done in the way of improving the running of a machine 'without touching 'either engine or transmission:
"For example, tyres. It is folly to run solid tyres down to the very last inch of rubber. It may be economy of tyres, but it is far from being economy of ' chassis. Cracked steel wheels, loose spokes in wooden wheels, loose rivets in frames', etc., may often be traced to running the tyres, which have not sufficient rubber to maintain their resilience, too long.
"If the:tyres.are in good order, turn your attention
to the frame itself. Any loose rivets, either in frame brackets, cross members or sub-frame should be cut out. If the holes have worn oval, they should he trued up with a 'reamer, and fitted with turned steel bolts to take the place of the rivets, than which they are more satisfactory. Inspect the springs. On the front springs take care that the centre bolt or bracket is registered properly with the recess in the front axle. Put a spanner on the nuts of the spring clips. If, for service overseas, the springs have been stiffened in order to withstand the abnormal road conditions there prevalent, remove one of the lower leaves, and improvement will'be noted. "Examine the swivel pinz of the steering gear. Have the front axle jacked up : test for wear sr the swivel pins or bushes by lifting the wheel, taking care,
however, that wear in the wheel bushes is not mistaken for wear in, the pivot. If there iE too much end play on the wheel bushes, fit washers, either fibre or metal. This, end play should not exceed sls. of an inch, which amount, bowever, is essential. If the front axle is of the built-up type, inspect the rivets. It these are not tight, replaceby turned bolts, as was
suggested in the case. of the frame. Line up wheels, and're-bush worn steering rod jaws.
" These are, a few directions in which improvement
on a used chassis can be effected. The body, however, is a considerable source of noise, and a lot can be done by giving attention to it. Generally, the need only •applies "to , small details, as, for example, the side doors, and in these, strips ot rubber, cut from an -old inner tube, if secured top and bottom of the doors, will eliminate a lot of rattle."