[Illustration]
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.
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.
[Illustration: MUNRO'S MACHINE TURNING LATHE FOR PLANING, ETC.]