THE GARAGE LATHE.
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Its Equipment for Special Jobs, as Described by Our Driver and Mechanic Readers.
THE ENGINE lathe, once the king of machine tools, has long since fallen from its high estate at any rate so far as the motor manufacturers -workshop is concerned, its place being usurped by "capstans," "turrets," and other plebeian fellows of that ilk.
It ubiquity, 'however its universal i application, is n no part due to its designer or manufacturer, but in neaeiy all cases is due to the ingenuity of him 'alio operates it and who himself must be, at one and the same time, turner, miller, driller, fitter and general mechanic.
In short, the present-day garage mechanic—I am speaking only of men who are worthy of their salt—has taken upon himself the mantle of the old-time
engineer, and by the simultaneous adaptation of himself and tools is able to perform any required operation for the benefit of his clientele. Readers of this page have from time to time, by courtesy of the Editor and the good nature of such mechanics, learned much concerning the means by which lathes may be converted for special purposes. Their knowledge on that same subject is further increased. by the communications which are printed here, to the writer of the first of which is awarded the 15s. prize.
The use of a lathe for cutting keyways is not new. Generally, however, some form of milling cutter is employed for the purpose, and special equipment of this kind may be bought. Milling, however, is the modern method of doing work which, in former days, was effected by shaping or slotting, according to the character of the work, and no doubt the same factor—simplicity—which operated to make straight-line movement popular in the old days, is still effective when the garage mechanic sets to work to make some jig or gadget by which he can, with the scant means at his command, carry out such an operation as the cutting or recutting of a keyway. The method suggested in a letter from " H.A.B.," of Rotherham, is of • the " shaper " type, but is, nevertheless, quite ingenious in its way. Its disadvantage, if we may say so, is that it demands manual labour for its operation, the lathe merely serving as a suitable support for the shaft which is to be keywsyed, The outlay involved in the construction of this fitting is pradically negligible, the material required being no more than a piece of flat bar steel, section 2 ins, by
in., and length about 2 ft. or more, according to convenience, and a special T-head bolt. The flat bar is shaped at one end to form a handle : at the other it is drilled to suit the bolt which holds the compound rest on the cross-feed rest. of the lathe. The T-head bolt is fastened to the slide rest by the tool bolts; it projects outwardly from the lathe and is engaged by a suitable slot, which, as shown in the sketch, is cut in the flat
bar. •
No explanation of the method of operation is needed, beyond stating that, aa.. a preliminary, the screw is removed from the compound rest, when the lever may be fitted and engaged, the rest then sliding to and fro.
seems to be rather a whale on lathe equipment. In another letter he describes a stepped eccentric mandril on which to mount eccentrics in need of a little truing up. It is a fitting which will be of use only in those shops which cater for steam wagon repairs, as only there will the mechanic .11e, called upon to deal with eccentrics varying_ as regards the diameter of the shaft on which they fit. and also as regards their eccentricity.
The mandril suggested, and illustrated by one of the drawings which are reproduced on this page, is designed to accommodate itself to variation of both dimen
sions. It is stepped in diameter from 2 ins. to 3 ins., the number and extent of the steps being made to suit the circumstances. The eccentricity is made variable by dovetailing a sliding bar into each end of the mandril. Two or three centres ere drilled into each bar, and any one of them used as is most con'venient. This permits of a maximiun variation in eccentricity with a minimum of sliding of the adjustable bar, which is firmly secured by means of a. setscrew. Other details will be apparent from the sketch, and it should be remarked that great accuracy is required in the manufacture of this Simplicity is the keynote of the tip which is embodied in a letter from "T.H.," of Holloway, who tells us that in the course of his work he has frequently to complete repetition fobs in
relying the boring, in the lathe, of holes, the depth of which is an important feature. Frequent measurement in order to eliminate risk of making too deep a hole proving rather a nuisance, he hit upon the idea offixing a small plate on the end of the slide rest, so disposing it, by careful .setting with a bar or pluggauge, that the plate made contact with the face of the pieee upon which he was working, when the right depth was reached. The location of the plate is well shown by the accompanying sketch, and the groove cut in the plate makes it difficult for particles of steel to get between plate and slide, thus disturbing the setting.
Lamps Alight.
On Saturday, April 15th, light your lamps at 8.23 in London, 8.37 m Newcastle, 8.31 in Birmingham, 8.46 in Edinburgh, 8.38 in Liverpool, 8.33 in Bristol, and 9.21 in Dublin.