[APPENDIX.]
[Professor Willis's Tool Holder for the Slide Rest.]
This—described and drawn first in "Holtzapffel's Mechanical Manipulation," to which work the author, and, indeed, most authors of books of the nature of the present, are indebted for much of their information—is now become very general, and from its perfect action ought to be universally used in all factories in which the lathe bears a part. It permits the tool to be set at any required angle upon the bed of the slide rest, and holds it securely when placed in position. It is likewise so constructed as to be easily removed from the table of the rest, so that other forms of apparatus may be attached if desired. One nut only has to be turned to fix the tool, this nut turning on a strong central screw, A, in the figure, the lower part of which, as far as the shoulder, is screwed into the top plate of the rest. This shoulder is directed to be made with flattened sides, so as to be capable of being unscrewed by the application of a wrench. The actual clamp is a triangular piece of cast or wrought iron, B, in the centre of which is a hole to allow this piece to go easily over the screw. The hole is hollowed out into a cup-shaped cavity, into which fits a hemispherical washer, shown at C in the section. The clamping nut, D, acts upon this washer, which permits the triangle to take up a position not necessarily quite parallel to the bed of the slide rest, and thus a tool whose upper and lower surfaces may not be strictly parallel will be securely grasped. The piece called triangular is not precisely of that form, but of the shape shown in the second figure, in which E, E, represent two hard steel pins, slightly projecting—one of these, E, appearing in the first figure. These pins rest upon the upper surface of the tool. At the third angle the clamping piece is drilled and tapped to receive a screw, which must work stiffly in this hole. Thus when a tool is placed in position, as shown, the clamping nut maintains a pressure upon the three points beneath the apices of the triangle. As thus arranged the tool would be stiffly and securely held; but Professor Willis has added a second triangular piece, nearly similar to the first, except that it is provided with a boss, in which a notch or groove is cut, K, in both figures, into which the point of the small screw falls. This lower triangle, which is free to revolve round the central screw, is also cut away at the line L, L, of the second figure, so as to form a guide or rest for the side of the tool, which is thus kept at the same distance from the central screw, and placed in a moment exactly under the studs or points of the upper plate. A careful inspection of the two drawings will make the precise arrangement clear. In making it, which is not very difficult, care must be taken to make the triangle of such size and so to place it, that no angle can overhang the top plate of the rest, in whatever position it may be. The hole in the upper triangle or clamp must be tolerably large and slightly conical—the base of the cone upwards, to allow this piece to take up a bearing, as described. The hemispherical washer is always in a horizontal position, and the hole through it may be only of sufficient diameter to allow it to pass freely over the central screw.
[Munro's Planing Machine to be attached to the Lathe, and worked with the foot.]
In the English Mechanic of Nov. 2, 1866, a brief notice was given of the above. The author of the present work having carefully inspected the machine and seen it in operation, considers it of such great value to the amateur mechanic, as well as to the professional turner of metal work, that he has had an engraving of the machine carefully made from a photograph, and has here appended it to illustrate the description given.
MUNRO'S MACHINE TURNING LATHE FOR PLANING, ETC.
It is a lathe for planing, cutting key-grooves in wheels, collars, &c., and cutting racks on the teeth of wheels. The lathe is of the usual construction, but outside the right hand standard is fixed a vertical spindle, which is made to rotate by a pair of bevel wheels, the pinion being fast to the end of the crank shaft, and in contact with a wheel of double the number of teeth on the vertical spindle. On the top of the latter is a crank-plate, which will give a stroke of ten inches or less at pleasure. The planing-machine is fixed by two bolts to the lathe-bed, and a connecting rod is attached to the sliding plate or bed of the planing machine, the other end of which is made fast to the pin of the crank-plate. The work is clamped by simple means to this sliding bed, and thus passes to and fro under the tool which, by self-acting gear, is made to traverse sideways after each stroke as in the large planing machines. The whole works almost noiselessly and with the greatest ease, each part being accurately fitted, and the whole well finished. For such purposes as planing the face of the slide valve and its bed in small engines, or shaping the guide bars of eccentric and other chucks, facing the frames of slide-rests, &c., it is exactly what is needed by the amateur, rendering the workshop complete for all purposes without the necessity for adding a large and separate planing machine, which takes up room that cannot always be conveniently spared. With such a lathe as that in the frontispiece, fitted with one of these planing machines, there is scarcely a model of machinery that could not be made. Any of our readers interested in mechanics would be wise to trip over to Lambeth and view the machine in operation; and the writer will guarantee, not only the most civil and obliging attention from the inventor, but the greatest pleasure and satisfaction from the working of the machine itself. There is a simple arrangement for key-grooving and slotting, by attaching the upper slide of the ordinary rest to the crank plate of this machine, in which case most of the apparatus is removed.