WAYS AND MEANS.
Page 67
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Useful Contributions From Our Driver and Mechanic Readers.
A Remedy for a Cracked Boss.
MLLE boss of a wheel on one of the 1 gearbox shafts will in some cases develop a crack, usually starting from one of the splines, or, in the case of a sprocket wheel, from the keyway. This defect is usually attributable to poor design, where the web of the wheel is all at one side, but is seldom met with in wheels that have the boss evenly distributed from the centre of the web.
A correspondent, " G.P.," of Harrow, has had the boss of a constant-me'sh wheel, on a 15-ewt, van which he drives, crack in the boss, the crack starting as usual at a keyway and terminating at the solid web. The crack did not prevent the wheel from running, but it caused it to become a slack fit upon its shaft ; so our contributor rightly decided to put matters in order. To do this he bored out a ring of mild steel so that it was .010 in. smaller tlian the boss, and formed a radius so that when hot it could be pressed on the toss until it came against the web of the wheel. By heating the ring to a dull red he was able to get it on to the boss, and he assures us that it then made the wheel a proper fit on its shaft.
Shrinking a collar on in this manner Is quite a common practice in certain classes of engineering, but we should advise anyone using the method to allow even less than the amount mentioned above, as if there he too much difference between the bore and the boss on which the ring is to be shrunk the former is likely to burst when cooling; .002 in. will be ample in most cases.
Fitting New or Recambered Springs.
DIFFICULTY is often experienced when fitting new springs or those that have been rehardened and set up to their original camber. The free camber of a new spring will often have the effect of shortening it so that it will not reach its shackle, unless some force be brought to bear on the spring. Levers are sometimes employed to take some of the free camber out of the spring, but they are not always very successful.
One of our readers, "0.0.," of Whitthigham, describes how he has managed to accomplish the operation of fitting new springs. He first fixed the spring at its front end in the usual manner and bolted it to its axle, he then got a jack under the axle, and raised the spring to a convenient height, placed a short jack between the spring and one of the bearers of the body, and by this means was able to depress the front end until it came within reach of its shackle, so that he could introduce the bolt.
Drivers and mechanics would not have such troubles to deal with if more care were taken in the design of a lorry, as it had been known for some time that shackles should be of sufficient length to allow the fitting of a spring without straightening it to make it reach its shackle.
A Practical Wheel Puller.
ONE of our correspondents, " W.J.R.,"
who hails from Sandbach, sends us a suggestion for removing the wheels of steam and other heavy wagons. He Points out that, although wheel pullers are made, they are not always to hand when wanted, and to borrow one usually means delay. Our own experience of wheel pullers is that they are seldom strong enough to remove a wheel from a heavy wagonl His plan is a simple one, and has the advantage that all the necessary appliances are always to hand wherever a steam wagon is in use. The jack Usually supplied with such wagons can be employed, and so can the steering chains, so all that is needed is to find a piece of steel to bear against the end of the axle, as shown at A, and securely to fix the chain to two opposite spokes, and then pass it over the end of the jack, taking care that it does not foul the collar provided for the tommy.
As such jacks are heavy to hold in place, it is well that the jack should be laid on a box or some such support while fixing up the chain. For smaller vehicles, steering chains may be too cumbersome, but a length of smaller chain is usually to be found wherever repair work is being undertaken.
Cleaning off Dirty Parts.
THAT much paraffin and wipings is wasted in the average repair shop is pointed out by " A.G.B.," of Bradford, who is a strict believer in having all parts thoroughly cleaned before allowing them to be placed on the benches where the fitting work is carried out. By this means he tells us that he is able to keep his fitters' benches as clean as those used for assembly in the works where the vehicles were made, and that through this he is in a position to keep better order and to remove the objection that some first-class fitters have to repair work.
We are glad to receive any suggestions of this kind, as we have always felt that much of the unpleasantness of the average repair shop is avoidable. His plan is a simple one, consisting of placing the parts to he cleaned in a bath of paraffin, and rubbing them over with a brush. For muddy parts a wire brush is found to be best. He then takes them outside and places them on the -stone paving of the yard, without wasting rags in trying to Clean off the paraffin. After.this he uses an ordinary hosepipe, pinching the end up with his fingers so that a small but high-pressure jet of water is produced, atitl plays upon the parts with the jet, driving all the dirt off them ; he then turns them over and completes the operation on the other side. After this, a little shaking will dislodge any water that may be clinging to the parts, and they are found to be far cleaner than any wiping with rags could ever get them. He tells us that the paraffin need not be clean, as all that it does is to loosen the dirt, the water does the rest. A great saving can be effected by this means, as rags are costly.