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. All notes are edited before being published. Mention your employers name, in confidence, as-evidence of good faith, Address. D., 2. and F„ "The Comniercial Motor," 7-15, Bosebery Avenue, London, E.G. 1.
Lamps Alight.
On Saturday, May 8th, light your lamps at 9.2 in
• London, 9.32 in Edinburgh, 9.21 in Newcastle, 9.20 in Liverpool, 9.11 in Birmingham, 9.12 in Bristol, and 9.57 in Dublin.
Converting a L.T. Magneto to H.T.
The sender of the following communication has been. awarded the extra payment of 5s. this week.
r2083] " H.E.T." (London, N.) writes :—" It will seldom fall to the lot of a commercial motor driver to have to make up a complete ignition set from, on the one part, an old L.T. set and on the other, an H.T. magneto of the" most modern type, -removed from an aeroplane engine. I cannot, therefore, put forward the following notes an likely to be of service to a large number of the readers of your P.M. and F.' page, but I think it will nevertheless be found. to be sufficiently interesting to claim a place on that page " The L.T. ignition set on the old van which I drive had been troublesome for a long while, and although it-was realized that the addition of an H.T. magneto would probably cure the trouble, it was felt that the expense which such a course would involve was hardly justifiable in the ease of a chassis of the age and -infirmity of this one. I happened to have by me, however, an M.L. magneto of the most modern type, but of special design, it having been removed from a nine cylinder Gnome engine, and constructed so that it gave two sparks per revolution. Moreover, the terminal was where the base usually is-; this type of magneto being customarily fitted upside down, or so it appeared.
"I decided, however, to try what could be done. I thought that by retaining the driving gear, distributor gear, and distributer of the old magneto and adding to it, in some way, the high-tension magneto as a generator, I could attain the end in view. In this I was eventually successful. I tackled the new magneto first, removing its driving sprocket, cutting off the rim, and brazing on to it another of a size which would allow of the drive being taken from the farge distributor wheel of the old machine. I also drilled the base'for four 1-in. tapping holes, which I afterwards tapped out.
"I made a double knee piece from mild steel plate, one flange of which I fastened in place of the armature cover of the old magneto, the other I bolted to the base of the new ino,•neto, the dimensions of the plate being such that, when this was done, the large wheel of the distributor gears on the L.T. magneto engaged with the new driving wheel of the H.T. mag neto. I .coupled. the. H.T. terminals of the two machines by means of a piece of copper wire, properly insulated, and then, having timed the whole outfit, had an ignition set which gave me results equal to the best H.T. magneto ever turned out."
A Steam Wagon Eccentric Repair,
[2084] " W.A.B." (Oldham) writes :—" I was interested recently to read on the "P.M. and F." page a description of a repair to a stub shaft of a steam wagon, and as I myself had an experience somewhat similar in nature a short time ago, it may be useful to recount it for the benefit of your readers.
"I recently had occasion to fit a new sprocket wheel on to my Foden wagon, and in the process of dissembling the gear, prior to fitting the, sprocket, I discovered, that the long sleeve which carries the eccentric was cracked right round its circumference, at the junction with the eccentric. I .understand that new%bushes are not difficult to obtain or fit, but 'as I wished to get the wagon on' the road again quickly, I decided to have "a shot at repairing the old one. I realized that ft was only necessary to. prevent the bush from revolving inside the sprocket and gears, the eccentric being driven by a gear wheel of the transmission gear, to which it was bolted. "As a preliminary, I removed the eccentric and bush and passed a in. bolt right through it and tightened the two broken pieces together. The jagged end of the beak was in a way a help towards getting the bush into it's correct position. I then drilled three holes right through from the plain side of the eccentric into the bush, -see sketch [Which we have had redrawn.—En.],_ and tapped them in. Whitworth.
"I then secured a stud into each hole, screwing it up tightly, and finally trimmed the end of the studs off flush with the face of the eccentric.
" A little. difficulty sometimes occurs when removing fusible plugs from steam wagon boilers. They are provided with square ends which are tapered. The consequence is that the box key does not always grip the head of the plug, and the mechanic is not sure that the plug is turning or whether the key itself is merely revolving on the outside of the square and taking oil the corners. I have found it a good tip to fix the key as well as possible en to the square, then pack it up from the floor with a, couple of stiff wedges so that it cannot slip off the square, and screwing up with the aid of a tommy-bar. '