IMPROVE- MENTS IN CUTTER HOLDERS FOR MACHINE TOOLS."
Year: 1880

page_text: LETTERS PATENT to Francis Murray Newton, of Eton College, Eton, in the
County of Bucks, Instructor of Mechanics, for an Invention of "IMPROVE-
MENTS IN CUTTER HOLDERS FOR MACHINE TOOLS."
PROVISIONAL SPECIFICATION left by the said Francis Murray Newton at
the Office of the Commissioners of Patents on the 23rd December 1880.
FRANCIS MURRAY NEWTON, of Eton College, Eton, in the County of Bucks,
Instructor of Mechanics. "IMPROVEMENTS IN CUTTER HOLDERS FOR MACHINE
TOOLS."
My Invention relates to holders for the tools or cutters used in various machine
tools, such as lathes, planing machines, shaping machines, and other machines for
the cutting and shaping of metal.
The holder consists of two principal parts, namely, a slotted bolt to receive the
cutter, and a bar suitably formed and bored to fit the smaller diameter of the
slotted bolt, and also to partially embrace and support the larger diameter or part
of the bolt. This bar is provided with two conical surfaces or parts of the frustra
of two cones arranged on the same axial line with their apices coinciding, but with
their bases turned in opposite directions. The slot in the slotted bolt is cut at an
angle of about 60° with the central line of the bolt, and consequently the cutter
stands at the same angle with the bolt, as do also the two conical surfaces which
make the same angle with their axis as the cutter makes with the slotted bolt.
In use the cutter, which is made from bar steel, preferring a somewhat tapered
cross section, is slipped into the slot and is tightly gripped (by turning a nut on
the bolt) between one end of the slot and the two conical surfaces. It may be
adjusted to any angle with the holder, within limits defined by the conical surfaces
which represent nearly one half (it may be more or less) of the circumferences of
the cones of which they are parts, the adjustment being made with the greatest
ease by slackening the nut and turning the cutter into any desired position, and
then tightening it.
I find it convenient in practice to bore my cutter holder, and cut the conical.
surfaces at one operation by the use of a cutter formed with a drill point, and with
cutting edges formed in the shape or profile of the two conical surfaces and the
hollow cylindrical part between them.
In some cases I bore the hole in the holder for the reception of the screwed.
portion of the slotted bolt first, and then I provide the conical cutter with a shank
to fit the said hole to guide and steady the cutter while it is cutting the conical
surfaces.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Francis Murray Newton in the Great Seal Patent Office on the
21st June 1881.
FRANCIS MURRAY NEWTON, of Eton College, Eton, in the County of Bucks.
Instructor of Mechanics. " IMPROVEMENTS IN CUTTER HOLDERS FOR MACHINE
TOOLS."
My Invention relates to holders for the tools or cutters used in various machine
tools, such as lathes, planing machines, shaping machines, and other machines for
the cutting and shaping of metal.
The holder consists of two principal parts, namely, a slotted bolt to receive the
cutter and a bar suitably formed and bored to fit the smaller diaineter of the slotted
bolt, and also to partially embrace and support the larger diameter or part of the
bolt. This bar is provided with two conical surfaces or parts of the frusta of two
cones arranged on the same axial line with their apices coinciding, but with their
bases turned in opposite directions. The slot in the slotted bolt is cut at an angle
of about 60° with the centre line of the bolt, or at such other angle as is suited to
the material to be cut, and the cutter stands at the same angle with the bolt, as do
also the two conical surfaces, which make the same angle with their axis as the
cutter makes with the slotted bolt. In use the cutter, which is made from bar
steel, preferring a somewhat tapered cross-section, is slipped into the slot, and is
tightly gripped (by turuing a nut on the bolt) between one end of the slot and the
two conical surfaces. It may be adjusted to any angle with the holder, within
limits defined by the conical surfaces, which represent nearly one half (it may be
more or less) of the circumferences of the cones, of which they are parts, the
adjustment being made with the greatest ease by slackening the nut and turning
the cutter into any desired position and then tightening it.
DESCRIPTION OF THE DRAWINGS.
Fig. of the Drawings shews in side elevation one of my improved tool holders
suitable for a lathe, whose centre is much above the top of the slide rest, and with
a short range for adjusting the tool to a limited horizontal angle with the shank of
the holder; Fig. 2 shews a front elevation, and Fig. 3 a plan of the same.
.
a is the bar or shank of the holder for securing it in position; b is a bolt formed
with a slot b', into which fits loosely the tool or cutter c. The bar or shank a is
provided with two conical surfaces d, e, or parts of the frusta of two cones arranged
on the same axial line with their apices coinciding, but with their bases turned in
opposite directions. The bolt is provided with a screwed part or extension b²
passing through a hole in the bar or shank, on to which screws a nut b³. The tool
or cutter c, which is preferably made of a somewhat tapered cross section, being
slipped into the slot b¹, is tightly gripped between one end of the slot and the two
conical surfaces d, e, by tightening up the nut 69 on the screw 62 of the bolt b.
The bar or shank where it bears against the bolt b is turned to an equal diameter
with the said bolt, so as partially to embrace and support it. The tool or cutter
may be adjusted to any angle with the holder (as, shewn in dotted lines, Figs. 3
and 6) within limits defined by the conical surface d, which may (as in modifica-
tions to be presently described) represent nearly one half of the circumferences of
the cones of which the surfaces d, e, are parts, the adjustment being made with the
greatest ease by slackening the nut 6 and turning the cutter into any desired
position and then tightening it; Figs. 4, 5, and 6, indicate similar views to
Figs. 1, 2, and 3 of a modification of tool holder in which the range of angular

page_text: adjustment for the cutter is increased by forming a projection a¹ on each side of
the bar or shank a, thereby increasing the extent of the conical surface against
which the cutter can bear.
Figs. 7, 8, and 9 illustrate three views of a short adjustment range tool holder
for a low centre lathe, and Figs. 10, 11, and 12 are three similar views shewing a
long adjustment range tool holder for a low centre lathe. Similar letters of
reference indicate like parts in all the views. I find it convenient in practice to
bore my cutter holder, and cut the conical surfaces at one operation by the use of a
cutter formed with a drill point, and with cutting edges formed in the shape or
profile of the two conical surfaces, and the hollow cylindrical part between them.
In some cases I bore the hole in the holder for the reception of the screwed portion
of the slotted bolt first, and then I provide the conical cutter with a shank
to fit the said hole to guide and steady the cutter while it is cutting the conical
surfaces.
Having described the nature of my said Invention, and the manner of performing
the same, I would have it understood that I am aware cutter holders have been
made having at the end of the holder and at a right angle to its length a hole in
which is fitted a bolt with a screw nut at the upper side, there being cut through
the axis of this bolt a slot at a suitable angle in which the cutter is placed, so that
when the bolt is screwed tight the cutter is drawn against a loose collar upon the
holt, and I do not lay claim to this arrangement, but my Invention is an improve-
ment upon such a construction of cutter holder, whereby I obviate the defect of
want of rigidity arising from the tool being gripped only by the loose collar, and
also by my Invention fewer parts are required, a loose collar being dispensed with.
What I claim is,―
Constructing cutter holders for machine tools with conical surfaces for the cutters
to bear against, substantially as above described and shewn in the accompanying
Drawings.
..
In witness whereof, I, the said Francis Murray Newton, have hereunto set
my hand and seal, this Twentieth day of June, in the year of our Lord
One thousand eight hundred and eighty one.