IMPROVEMENTS IN ROTARY CUTTING TOOLS
Year: 1885

page_text: I, ALEXANDER MELVILLE CLARK, of the firm of A. M. and Wm. Clark, of
53, Chancery Lane, in the County of Middlesex, Fellow of the Institute of Patent
Agents, do hereby declare the nature of the said Invention for IMPROVEMENTS
IN ROTARY CUTTING TOOLS a communication to me from abroad by La Société
Heilmann-Ducommun and Steinlen of Mulhouse, Machinists, to be as follows:-
"
This Invention relates to rotary cutting tools or heads having removable cutters
arranged either in a cylindrical or conical form and inclined at an angle to the axis
of the tool.
Reference is to be had to the accompanying drawings forming part of this
Specification wherein figure 1 represents an elevation and also a detail section and
figure 2 a plan of a cutting tool or head of conical form and of small diameter.
Figure 3 represents an elevation and figure 4 a plan of a tool of similar diameter
and of cylindrical form. Figure 5 shows a section and elevation and figure 6 a
plan of a tool of large diameter, Figure 7 shows the arrangement of the removable
cutters and set screws.
The tools shown in figures 3. 4. 5. 6 are intended for endwise work and consist
1st of a central part a having grooves cut in the periphery of triangular form to
receive the cutters b, this central part a being in one with the stem c in the case of
a tool of small diameter, such as that shown in figures 3 and 4; it is screwed on
the end of the tool spindle in the case of tools of larger diameter such as that
shown in figures 5 and 6.
2nd Of a series of cutters b. received in the grooves of the part a; these cutters
are made of rods of steel drawn of equilateral triangular section and the position
of the grooves which hold them is such that they occupy without adjustment the
best position to take a good cut.
3rd Of a ring d shrunk tightly onto the central part a of the cutter stock or
head and provided with set screws e¹ to hold the cutter in place.
The cutters are so arranged around the cutting head that the faces m, n,
and m, p, respectively form with the radius passing through the point m, and with
the tangent thereto angles of 15°. These cutters are so inclined as to make with the
Di 11

page_text: axis of the tool an angle of 20° as shown in figure 3 this inclination being the one
which gives the best cut. The cutting end of each cutter is ground to such an
angle that there will be a clearance behind the cutting edge equal to about 3° or 4°,
the cutters being for this purpose ground upon a special machine whereby a uniform
angle is ensured.
The axes of the set screws shown in figure 7 also make with the radii passing
through them angles of 15° the screws thus being perpendicular to the side against
which they press and their heads are wholly contained in recesses in the periphery
of the ring c.
The tools cutting at the end and side shown in figures 1 and 2 are used when
it is required to work out a corner, the tools before described not admitting of this
on account of the thickness of the outer ring d. In this case tools are used in
which the cutters are both inclined to the axis, and also outwards from the centre
to the circumference so that they collectively form a cone of which their cutting
edges are the base. With this form of tool a cutting part is obtained of greater
diameter than that of the ring of the stock or head. The cutters in this case are
ground with two cutting edges one tu parallel to the axis of the tool, and, the
other r, 8, perpendicular to said axis, with a clearance behind both cutting edges
of 3° or 4°.
In order to tighten the cutters towards the cutting end, there is applied to each
cutter a small rocking lever oscillating on a fulcrum g and operated by a screw k
tapped into it whereby when the screw is tightened up it draws towards it the
limb f g of the lever and so causes the limb gh to bear against the cutter at h.
At the rear end of the cutter set screws similar to those before described may be
used. This tool has the advantage over the one previously described of being able
to work out a corner and also of boring out a hole whose diameter is that of the
tool which may be increased or reduced slightly by causing the cutters to project
more or less from the end of the cutter head, but does not accomodate so many
cutters as the preceding one as they interfere with one another near the spindle.
Moreover their length is necessarily limited.
The advantages of these improved tools are:-
1. That the cutting edges may be placed at the best angle for cutting and for
clearing the cuttings.
2. The cutters are very firmly held and can be easily put in place and adjusted.
3. Forging and adjusting to give the cutting edge the proper direction are
dispensed with, thus enabling very hard steel to be used.
4. The cutters may be at once easily and accurately ground.
5. The cutters are easily renewed when damaged.
6. These tools may be used of all sizes upwards from a diameter of 24 inches at
the cutting part, which diameter may even be reduced.
7. The conical form of tool may also be used for boring out or enlarging holes.
Dated this 1st day of July, 1005

page_text: I, ALEXANDER MELVILLE CLARK, of the firm of A. M. and Wm. Clark, of
53, Chancery Lane, in the County of Middlesex, Fellow of the Institute of Patent
Agents, do hereby declare the nature of this Invention (a communication to me
from abroad by La Société Heilmann-Ducommun and Steinlen of Mulhouse,
Machinists,) and in what manner the same is to be performed, to be particularly
described and ascertained in and by the following statement :-
This Invention relates to rotary cutting tools or heads having removable cutters
arranged either in a cylindrical or conical form and inclined at an angle to the axis
of the tool.
Reference is to be had to the accompanying drawings forming part of this
Specification wherein Figure 1. represents an elevation and also a detail section
and Figure 2 a plan of a cutting tool or head of conical form and of small diameter.
Figure 3 represents an elevation and Figure 4 a plan of a tool of similar diameter
and of cylindrical form. Figure 5 shows a section and elevation and Figure 6 a
plan of a tool of large diameter. Figure 7 shows the arrangement of the removable
cutters and set screws.
The tools shown in Figures 3. 4. 5. 6. are intended for endwise work and consist;
1st of a central part a having grooves cut in the periphery of triangular form to
receive the cutters b this central part a being in one with the stem c in the case of
a tool of small diameter such as that shown in Figures 3 and 4 but which is
screwed on the end of the tool spindle in the case of tools of larger diameter such
as that shown in Figures 5 and 6; 2nd of a series of cutters b received in the
grooves of the part a; these cutters are made of rods of steel drawn of equilateral
triangular section and the position of the grooves which hold them is such that they
occupy without adjustment the best position to take a good cut; 3rd of a ring d
shrunk tightly on to the central part a of the cutter-stock or head and provided
with set screws e to hold the cutters in place. The dotted lines in Figures 1. and 3.
represent a removable plate for setting the cutters.
The cutters are so arranged around the cutting head that the faces m n and m p
respectively form with the radius passing through the point m and with the tangent
thereto, angles of 15°. These cutters are so inclined as to make with the axis of
the tool an angle of 20°, as shown in Figure 3, this inclination being the one which
gives the best cut. The cutting end of each cutter is ground to such an angle that
there will be a clearance behind the cutting edge equal to about 3° or 4°, the
cutters being for this purpose ground upon a special machine whereby a uniform
angle is ensured.
The axes of the set screws shown in Figure 7. also make with the radii passing
through them angles of 15° the screws thus being perpendicular to the side against
which they press and their heads are wholly contained in recesses in the periphery
of the ring d.
The tools cutting at the end and side, shown in Figures 1 and 2 are used when
it is required to work out a corner, the tools before described not admitting of this
on account of the thickness of the outer ring d. In this case, tools are used in

page_text: which the cutters are both inclined to the axis and also outwards from the centre
to the circumference so that they collectively form a cone of which their cutting
edges are the base.
With this form of tool a cutting part is obtained of greater
diameter than that of the ring of the stock or head. The cutters in this case are
ground with two cutting edges, one t w parallel to the axis of the tool, and the
other 8 perpendicular to said axis, with a clearance behind both cutting edges
of 3° or 4°. In order to tighten the cutters towards the cutting end there is
applied to each cutter a small rocking lever (see Figure 1) oscillating on a
fulcrum g and operated by a screw k tapped into it whereby when the screw is
tightened up it draws towards it the limb f g of the lever and so causes the
limb g h to bear against the cutter at h. At the rear end of the cutter, set screws
similar to those before described may be used. This tool has the advantage over
the one previously described of being able to work out a corner and also of boring
out a hole whose diameter is that of the tool, which may be increased or reduced
slightly by causing the cutters to project more or less from the end of the cutter-
head, but does not accommodate so many cutters as the preceding one as they
interfere with one another near the spindle. Moreover, their length is necessarily
limited.
The advantages of these improved tools are -1st That the cutting edges may be
placed at the best angle for cutting and for clearing the cuttings. 2nd The cutters
are very firmly held and can be easily put in place and adjusted. 3rd Forging and
adjusting to give the cutting edge the proper direction are dispensed with thus
enabling very hard steel to be used. 4th The cutters may be at once easily and
accurately ground. 5th Any one of the cutters can be easily replaced when
damaged. 6th These tools may be used of all sizes upwards from a diameter of
2 inches at the cutting part which diameter may even be reduced. 7th The
conical form of tool may also be used for boring out or enlarging holes.
Having now particularly described and ascertained the nature of the said
Invention and in what manner the same is to be performed I declare that what
I claim is
A rotary cutting tool having a group of removable cutters arranged either in
cylindrical or conical form and consisting essentially of a cylindrical or conical
head a having grooves in the periphery in which the cutters bare fixed as
described the grooves having such directions that the cutters will be held
obliquely at a constant angle to the axis of rotation either in the form of a
cylinder or cone, substantially as described and illustrated in 'the drawings.
Tthis at dose of auch 1000