GARAGE AND WORKSHOP NOTES.
Page 69
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Useful Contributions from
Our Driver and Mechanic Readers.
Obviating Backfires.
MBERE are many instances of drivers and mechanics being injured through engines back-firing when being started by hand, and to obviate
such accidents " of New Malden, has devised a scheme which deserves deep consideration. The main details of the device can be seen from the sketches, which are, of course, purely diagrammatic, in makingthe safety mechanism an ebonite or fibre plate of approximately 3 in. by 4 in. dimensions is fitted with a ring of metal of small section, cut away from 7 o'clock to 12 o'clock on its circumference.
This plate is drilled with a centre hole large enough to allow it to pass over the sliding section of the startinghandle shaft, and is supported by a bracket or brackets (made according to circumstances). It should be in such it position that a brass clip with a springy contact, and mounted at the starting handle shaft, will slide on the face of the plate of insulating material only while the handle is pressed in for starthig.
if a duplicate lead be then taken from the terminal on the magneto contact-breaker cover and soldered to the Partial ring of metal the magneto will only spark when the handle• is being pulled up, thereby gaining all the advantages of the swing without the risk of kicking.
Two Useful Garage Tools.
01.it correspondent, " of
Rotherham, sends us a description of two garage tools which he has found help hini in his work, and which he suggests should form part of the equipment of every workshop where motor repairs are carried out.
Iii reassembling engines after overhauling it is often necessary to ascertain the position of the piston in the cylinder, so as to be sure it is at its highest point, as that is where all timing calculations usually start from. " II.A.B." takes a piece of any metal and turns the end to fit the thread of the sparking-ping hole ; he-then fits a piece of glass tube to this and makes a plunger with a collar and spring at its lower end and a pointer at the.top. With this lie can always be sure of the position of the piston when near its highest point.
The divisions on the tube he makes by nicking with a file.
We see no particular reason for the glasS tube, and think that if the plunger had a flat side and the divisions were marked on this the tool would be quite as useful and would be less likely to be broken.
The other suggestion sent in by the same correspondent is what is commonly known as a "stud-box," which is a tool used for screwing studs into their place, without in any way damaging the stud. This tool is supposed to be useful for taking out studs, but in reality most meehanics find that a foot-print or Stillson wrench is better for studs that have been exposed to heat, and prefer to fit a new stud if the gripping jaws have darnag,ed the old one.
The stud-box, as described by our correspondent, is formed out of any piece of square or hexagon steel about three times the diameter of the bolt in length. This is tapped right through, and an ordinary setscrew is placed in the top and allowed to -bear on the end of the stud. The stud should be screwed halfway up the box, met by the end of the setscrew and power applied to the head of the screw to drive the stud home. If the body of the box be held by a spanner while the screw is slackened the box can be unscrewed without fear of loosening the stud.
A Dennis Fan Improvement.
AN idea for improvingthe Dennis
subsidy type fan adjustment is put forward by " Sit.B.," of Stokenchurch. In the first place he says it is a good plan to make a support for the fan standard. This can be constructed from fin. steel, slit at the bottom, splayed open, and drilled to fit on to the cylinder water-pipe flange. The fan standard is drilled and tapped to receive a fin. stud at the top end. Next the fan socket must be dealt with. A fin. hole is tapped at each side, and a piece of steel of 1 in. by in., is made to the shape of a U. in each leg of which is drilled a fin, hole, whilst a fin. tapped hole is made in the centre. The various parts are assembled as shown in the sketch and fan-belt adjustment is effected by means of a long fin, bolt and lock-nut. This arrangement enables adjustments to be made without the use of the hammer, which is generally necessary, also it saves the fan from slipping down and fouling the bottom portion of the radiator if the locking screw should work loose at any time.
Removing Ball Pins. WE always welcome criticisms of the suggestions offered in this page, as, although the original letter may contain a useful suggestion, it is quite possible that another correspondent may make a still better suggestion. "J.L.P.," of Edinburgh, says that the suggestion made by " A.C.," of Nottingham, that a block of wood and a taper wedge are a good means for supporting a ball pin while the lever is being driven downwards can he improved upon by replacing the block and wedge by an ordinary Screw-jack, which forms a more solid anvil.
"J.L.P." also tells us that when dealing with overhead valves he has found that their seatings require touching up with a cutter more often than side-byside valves, and as it is not always easy to keep in stock a complete set of valve cutters he has in some cases improvised such a cutter by taking a new spare valve, filing cutting teeth on its seating face, taking care not to depart from the correct angle, and case-hardening it. The stem was then screwed with a die for a sufficient length to allow a holder to he screwed On, and a fairly efficient cutter thus made. A spring washer is used under the nut which forms the means of driving, and the teeth are so cut that the nut will screw on while act cutting of the seat is being done.