RUNNING, UPKEEP AND OVERHAUL.
Page 31
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Interesting Contributions from Maintenance Engineers, Drivers and Mechanics.
A Useful Attachment to a Power Hacksaw.
NVE hear from " A.A.," of Birmingham, that the power hacksaw
which he has to use in his work has no arrangement by which it automatically stops when it has finished its cutting. The absence of any such device causes much time to be wasted watching the saw and waiting for it to be clear for another job, so our correspondent rigged up an electric arrangement by the use of which he hears a bell ring on the completion of each cut.
His sketch makes the matter clear, as a string which is tied to the piece to be cut off, actuates a switch. A battery and a bell complete the outfit. Our correspondent does not make it clear what becomes of the string when a heavy piece of metal is dealt with; we should think that this would break the string every time.
We see no reason why the string should not be attached to the nonsliding frame of the machine, which always drops a considerable distance when the cut is finished.
" We have seen an old brake drum fixed up so that the falling piece strikes it and causes a gong-like sound.
A Suggestion for a Dust-proof Refuse-collecting Wagon. AREADER, " AsH.," of Horwich, ' sends us a suggestion for a body cf a refuse-collecting wagon in which the contents are not exposed to the atmosphere after once being thrown in. An endless chain, running over suitable rollers and driven by means of a clutch from the engine, follows the path shown in the drawing. A door is provided just behind the driver's cab, through which the refuse bins can be emptied into a chamber with a curved bottom, • so arranged that the scoops attached to the chain shall pick up any refuse and carry it over towards the centre of the body, where it is dropped from the scoop.
To discharge its contents the rear portion of the body only need be tipped, the chain and its supporting structure can remain in position. We are glad to see that the more hygienic collection of house refuse is attracting attention, for unless we wake up to the importance of the matter we shall one day find the foreigner so firmly planted here that it will be difficult to dislodge him, the matter having received so much more attention on the Continent than it has in this country up to she present time.
Adjusting the Dennis Transmission Brake.
IN our issue dated September 4th we published a suggestion regarding adjustment of a Dennis transmission brake. With reference to this tip it is pointed out by " H.B.," of Salisbury, that the brake shoes on Dennis vehicles of this type do not have linings as was suggested by our correspondent, and that it is inadvisable to shorten the hold-off spring in the manner suggested. When this spring is fully compressed by the adjusting nut, it is time that the shoes should be renewed.
The springs supplied are of standard length and there is practically no variation in the machining of the slippers, whilst the distance between the centre of the swivel-pin hole and the braking surfaces is constant. When the wear on the shoes is such that the spring is fully compressed, the thickness of the slippers is so reduced that permitting further wear is not advisable.
The Adjustment of Taper Roller Bearings.
A FEW weeks ago we published a letter from "H.W.C.," of Cosham, showing a method he had used for the adjustment of taper roller bearings. His plan consisted of fitting a sleeve over that part of the shaft which lies between the two inner rings of the bearing.
so that a solid abutment was provided whereby the two rings could be firmly gripped at auy desired distance apart. A correspondent, " K.C.," of ?oral, Rhondda, disagrees with this plan and points out that in his opinion the two inner rinks of the bearing should not be gripped, but should be allowed to creep around on the axle so that the wear of the rollers may be distributed all around the ring.
We are inclined to agree with " H.W.C.," as in the case of the bearing rings being gripped all weails confined to parts which are renewable, whereas if the rings be allowed to creep around, wear takes place on the axle itself, which is not looked upon as a renewable part. The objection raised by " K.C." can be overcome by giving the rings a half turn after a period of wear.
The Need fcr Care When Decarbonizing.
AUSEFUL warning is given by
" C.A.B. " of Woodbridge, Suffolk, to those who have to remove the carbon deposit from engines which are fitted with removable. heads. He points out that small particles of carbon may be left hanging about in ungetatable places and that when such particles get under an inlet valve they may necessitate the removal of the head and going over all the work a second time, for to leave such a particle under an inlet valve will often result in a burnt valve.
With an engine that is fitted with valve plugs the matter is a simple one. He suggests that in such engines special care should be taken and that blowing out all parts with a blow pipe and washing with clean paraffin are better than wiping with fluffy cloths, as the fluff may accumulate in the sump.
Ordinary sponge cloths are about the most unsuitable things with which to wipe out engine cases and should never be used. If cloths have to be used at all, old well-washed rags are best, but for the particular purpose of removing carbon dust from a cylinder head we have seen nothing to beat a bath of clean paraffin applied with a paint brush, following this by laying the head on the ground and playing upon it with a high-pressure jet from the end of a pinched-up hose pipe, taking care that the water flows through all the passages where carbon dust may lurk.