For DRIVERS, MECHANICS & FOREMEN.
Page 27
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TEN SHILLINGS is paid to the sender of any letter which we publish on this page, and an EXTRA FIVE SHILLINGS to the sender of the one which we select as being the best each week. AU notes are edited before being published. Mention your employer's name, in confidence, as evidence of good faith. Address, D., M. and P.. "The cemzmercial Motor," 7-15, Rosebery Avenue, London, E.G. 1.
Lamps Alight.
On Saturday, June 12th, light your lamps at 9.45 in Loudon, 10.25 in Edinburgh, 10.12 in Newcastle, 10.9 in Liverpool, 9.59 in Birminglihm, 9.55 in Bristol, and 10.52 in Dublin.
Mounting Wheels on Tubular Axles.
The sender of the following communication has been awarded the extra payment of 5s, this week.
[2,098] " 14Ieohanic " (Honey) writes :—" If there was one part of the live-axle chassis which gave consistent trouble on the W.D. vehicles in France it was the screwed ends of the tubular .axle cases, where fitted the nuts which served to retain the wheels in place. No doubt much of that trouble was one result of the execrable condition of the roads, which caused, a considerable amonnt of side strain on the wheels, and by the constant hammering to which this gave rise, stripped the fine threads which were usually cut on those axles. The general effect was sudden and unpremeditated removal of a wheel ; breakage of the lower half of the brake shoe ; distortion of the axle 4ase ; and bending of the axle shaft itself. The amount of the a.ctual damage varied according to the circumstances.
"In a previous letter used on the DAL and F.' page I described how I was able to effect a good and lasting repair to any axle which suffered in that way. Prevention, however, is better than cure, and I now propose to show how the accident may be averted by a little forethought when erecting the wheels In place. The accompanying sketch—Minch we have iad redrawn.—ED.]—shows the usual arrangement of the parts. It will be noted that there is an inner thrust washer, close to the brake shoe dust cover ; an outer thrust washer, backed by a lock-nut which is finally secured by means of a split-pin. It should further be noted that the outer thrust washer fits against a shoulder on the axle MSC My experience goes to show that the wheel is rarely assembled on the axle as it should be, and particularly have IL noticed the tendency to leave the washer clear of the shoulder, which it should not be. Generally. I have found the nut is screwed up until
the wheel turns freely against the collars, with a certain amount of clearance, when the split-pin is fitted in place and the job left.. This is surely wrong, for it leaves the nut free, and resting only on the split-pin, instead of its being locked solid, as all nuts should be. A systematic and practical way of doing the job is as follows :—
" Remove the road wheel altogether, then replace the two thrust washers. Lock the outer one up to the shoUlder on the axle, as tightly as it will go. When tightly secured in this fashion, drill it for the 5-32 in, split-pin' penetrating the axle tube as shown in the sketch. Mark the nut and end of the axle tube with a line so that the precise positions can easily be found when erecting the whole equipment subsequently. Next measure the distance between the faces of the two thrust washers, and also the corresponding dimension from face to face of the wheel bearing. The former dimension will be found to be the greater by a small amount, which is the thickness of the packing washer which should be placed between thrust washer and wheel. The work may then be re-erected with ale necessary packing washers, and the niebhania may he sure that the lock nfit will not come loose, or the thread be stripped. "If the end play between wheel and -plain washer is found to be more than 1-32 in. or -116 in., it is a good plan to recess the. outer washer to that extent, thus eliminating the need for a separate packing washer. If the tnrust washers are worn they should be renewed, and not allowed to get too thin. Above all things, when erecting wheels on axles of this type, remember to see that the lock-nut is screwed up tight against the shoulder It makes all the differ.lace between -a goad job and a bad one."
Getting Home on One Cylinder with a Steam Wagon.
[2,099] " RM." (West Bromwich) writes :—" In reference to the letter-which appeared under the above heading +irCy-our issue of May 18th, I venture to suggest that the writer has omitted to mention some of the alterations which he carried out in order to be able to..run home, using the h.p. cylinder only. Different makes of engine require different alterations we all know, but one thing is certain whether it is
the cylinder or the 1.p. cylinder Which is in use, there must be a passage through which the exhaust steam from the working cylinder may pass to the atmosphere.
"Now, if, as A.J.D.' states in the letter to which I refer, the 1.p. piston was blocked in place by a piece of woad, and the bp. valve not removed, then the necessary exhaust passage would not be available, and trouble Would result. Just ex-aetly. what would happen I am not sure, but it seems to me that steam from the h.p. cylinder would go on accumulating in the blocked .1.p. cylinder until the back pressure thus caused exceeded, or at least equalled, that of the incoming steam from the boiler, when the engine would cease to work. "As, however, A.J.D.' tells us he managed to drive home with his engine in its maimed state, and as he can hardly be mistaken an that point, I think he must have removed the 1.p. valve before he set out for home, but forgot to mention that fact."
f" H.M." is not quite correct in his ideas of what went on in the 1.p. cylinder, presuming the valve was left in place. We should be interested to learn, however, whether "A.J.D." really did remove the valve, and; furthermore,. should welcome other letters deal ing with this point.—En.]