For DRIVERS, MECHANICS & FOREMEN.
Page 29
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To Contributors.
We wish to draw the attention of contributors to this page to the new conditions of payment as set out in the heading. We are often asked by readers to extend the space given to this feature, but we would rather encourage brevity so that a number of letters can be dealt with weekly. A suggestion which we will adopt is the payment of an extra fee of half a guinea to the sender of a letter whieh opens up a useful discussion in this page.
Lamps Alight.
On Saturday February 7th, light your lamps at 5.26 in London, 5.17 in Edinburgh, 5.15 in Newcastle, 5.27 in Liverpool, 5.39 in Birmingham, 5.36 in Bristol, and 6.13 in Dublin. .
A Double-reduction Axle Fault.
The sender of the following communication has been awarded the extra payment of 5s, this week.
[2,052] " F.N." (Guildford) writese" I have nothing but praise for the double-reduction axle as employed on many commercial vehicle chassis, but, like many another good thing, it has its minor defects and drawbacks. T.h.e point which I am about to make against one of thesn was a very minor detail in itself, and the remedy -which I adopted for it was a simple one, hut I am gratified to learn that the makers of the chassis
have now, whether as the result of seeing one ef my doctored axles or not I do not know, nor is it material, adopted my method exactly.
"The countershaft which carries the crown bevel wheel and the spur pinion is turned down in diameter at each end. At one end it is carried in a ball bearing, while at the other end is a ball -hearing and also a thrust hall race. The ends are screwed 20 threads per inch to accommodate the locking nuts, and to secure the latter in place locking rings are fitted. These rings are 1-16 in. thick and are formed with an inwardly projecting tongue or key, which fits into a groove or keyway which is cut into the shaft. The outside edges of the locking rings are slit radially at intervals, so that a piece may be turned over to engage with one or other of the castellations on the outside of the round nuts which hold the ball bearings in place.
"Unfortunately, what always seemed to happen was that either the key of the ring broke off or else the turned-overnpieee of the ring, cracked off. At any rate, the locking was not permanent and shortly the nut itself would slack back, and ultimately the gear became disengaged. Well, I set about to remedy the thing myself, and this is what I did :— "1 bored each end of the countershaft up for a distance of about an inch, the diameter of the hole being 11 in. I assembled the ball bearings and gears in place on the bench and purposely left off the locking rings, as I proposed to do withent them. I then drilled right through each nut and shaft a 3-16 in. hole. Into each hole I fitted split pins.
" The split pin must 'be pushed in from the inside, as there is not sufficient clearance to allow of its being put in from the outside. True, the short turneddown end of the shaft can_ be completely erected on the bench and so placed in position inside the axle case. The other, however, cannot be so treated, but • must be fitted tip in place. When drilling the splitpin holes they should be put through the castellations on the round nuts, as that position allows more room for the end of the split pin to be opened out.
"It is advisable to drill two or three holes in the nuts so as to allow a little latitude for screwing up later on although, as a matter of fact, I have just inspected one of these altered axles after 18 months' wear, and there is not a shake near it, and certainly no chance for screwing up one of the nuts in question. "Incidentally, you may be interested to know that I have had 68 vehicles of This type pass through my hands, to all of which the alteration was made.
When Relining Brakeshoes.
[2,o53] " B.J.0." (Hammersmith) writes :—" When relining brakeshoes or other fibrous material, it is most essential that the lining be stretched tight during the process of securing in place. elly method is as follows :—I secure one end of a length of lining to the shoe, using a couple of rivets. I then bend the lining round the shoe and place the overlap in the vice in such a position that it draws the projecting corner of the shoe against the face of the vice. By pullingldown this upon the outer end of the shoe, it turns upon the vice jaws as upon a fulcrum, and the lining can be stretched and tightened to any required degree. Hold it tight by some means, and drill and fit rivets at the_ opposite end of the shoe. When a short piece of lining is being used up, and there is no overlap to grip in the vice, hook some substantial wire into the end of the liner, and grip the wire in the vice jaws as in the other case the overlapping end of the liner was gripped."
Charging Accumulators at Home.
[2,054] " M. J. " (Kingston) writes : —" Although I do not recommend the charging of accumulators from the electric lighting circuit, yet it is sometimes useful to know how this may be done. "If the current. is continuous—and, incidentally, accumulators can only be charged from a continuous current—take a switch controlling two or three lights and put the handle in the ' off ' position, connect each side by wires to the accumulators, finding the polarity by a method which I will explain. The handle of the ;switch must remain in the 'off' position whil ist charg g. A 220 volt supply will require about seven 16 c.p. lamps.
"To find the polarity, use pole-finding paper, which must be wetted. The negative pole is indicated by a, red mark.
"Another method is to clip the wires from the switch into slightly acid or salt water. The wire connected to the negative side of the switch will give off bubbles of gas."