MEANS AND METHODS WHICH SAVE LABOUR.
Page 29
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Some Useful Contributions From Our Driver and Mechanic Readers.
-UIROM Chippenliam "
sends us some notes on milling keyways and splines on shafts. He points out that this work really requires no great skill, and can be carried out on almost any lathe, providing this be fairly accurate.
The shaft in which the keyway is to be machined or the splines to be cut is secured firmly to the lathe saddle by means of the tool-holding clamps, as shown in Otir illustration, and packed up so that the centre line of the shaft coincides with the lathe centres. This can best be ascertained by employing a scribing block on the lathe bed and producing the centre line on each side of the shaft. The block is first set to the lathe centres, and the shaft is then set so that both centre lines coincide with the scriber.
When cutting splines the shaft is moved to a new position for each successive operation, and the scribing block is used to ensure accurate setting for each. The milling cutter is held in the chuck and the lathe set in motion. Movement of the work across the end of the rotating cutter is effected by the traversing screw and light cots only should lae taken; a lubricant composed of water and phynol or a little light machine oil should be used.
An adjustable ,tap wrench is always a useful tool in a repair shop, and one which is simple to make and effective in use forms the subject of another hint by "W.A.S.W." To construct it, a piece of 1-in, by a--in. mild-steel bar is drawn out at each end to form handles, leaving the centre of the same eection as the original bar. This portion is then cut to shape in the manner shown, and another of -5---in. steel bar is fitted into the gap. The main part is thee drilled and tapped Whitworth, and the detachable piece drilled correspondingly, but with 11-in. clearance holes.
A V-shaped groove is cut in each portion, the size of this varying according to the class of tool with which the wrench is to deal. It will be found advisable to mark off these " V" grooves when the detachable piece is securely held in position by the set-screws which are employed for tightening the halves of the wrench. This will ensure them being in alignment.
THE extraction of a broken tap is often a matter of great difficulty, and amongst the best means which can to adopted for the task is that suggested by " A.L.," of Baildon. As a matter of fact, it is one which we have ourselves employed in the workshop ; but, as it may not be known to all our readers, we do not think space will be wasted in referring to it.
A piece of tube of approximately the same outside diameter as the hole which is being tapped should be procured, and from this 'about 11 in. cut off. , Three or four slots, according to the number in the tap, should be cut in one. end, each dot being approximately the same width as the teeth in the tap, thus leasing prongs which after a small amount of filing will fit into the grooves of the tap.
If the tube be large enough, a hole can be drilled, through it near the top for a tommy-bar, but if too small for this, the top may be squashed in the jaws of a hand vice or held by a pair of Footprints. By carefully rocking the tap it can in most instances be backed out of the hole.
A SIMPLE but useful device for checking front-whtel alignment is used by " W.G.B.," of London, W.C. It consists of a strip of wood lj in. wide
and with a thickness of in. The overall length can be approximately 41 ins., and this will include a part shaped to form a handle. At the other end should be secured, by two screws, a small piece of angle steel or iron to form a hard-wearing stop, whilst towards the handle end and in a position which can best be determined by actual test on the vehicle should be painted alternate stripes of black and white, each in. in width. When the gauge is in use, one end is pressed against the wheel rim at the front, and it is a simple matter to note the position of the front rim in relation to the black and white stripes. The gauge is then employed in the same manner at the backs of the wheels, and any discrepancies between the two measurements can at once be noticed. The task is, of course simplified if the wheels be of the spoke type. With disc wheels the gauge can be used satisfactorily if a little more care be exercised.
WITH a commercial-vehicle engine it is sometimes a difficult matter to replace it in the chassis after an overhaul when blocks and tackle or a crane be not available. Recently of Lower Spennymoor, was faced with this task in connection with an engine belonging to a 15 ter Fiat The work was being done in an open yard, and to overcome the difficulty he obtained a short ladder and allowed one end of this to rest on the front crossmember of the frame. The hand brake of the vehicle was put on to avoid any danger of slipping, and a stout plank was laid along the ladder, covering the rungs. Packing, consisting of blocks of wood, was also put under the centre of the ladder to prevent this from bending. The plank was then greased and the engine slid on to the plank, flywheel foremost. Two men and a boy were able to slide the engine up the plank, and the top of this was allowed to tip over until both the crankcase arms at the rear rested on the sub-frame.
No diffitulty at all was experienced in carrying out this process, but it was found essential to diSconnect the two pins which hold the steering column in position and to remove the steering box, which is carried on the shassis by two bolts.
IN a par;raph by " D.D.I.," of
Cleckheata, which we published in our issue -dated July 130a, reference was made to an adapter for using ordinary machine drills in a ratchet brace. We now reproduce a drawing which may assist those who wish to use this device.