Improvements in Tool-holders or Cutter Bars for Lathes.
Year: 1899

page_text: Date of Application, 25th Apr., 1899-Accepted, 10th June, 1899
COMPLETE SPECIFICATION.
Improvements in Tool-holders or Cutter Bars for Lathes.
I, HANS JOHN STEPHEN CASSAL, of 20, St. George's Square, Primrose Hill,
London, in the County of Middlesex, Journalist, do hereby declare the nature
of this invention and in what manner the same is to be performed to be particu-
larly described and ascertained in and by the following statement:-
This invention relates to improvements in cutter bars or tool holders for
lathes and has for its principal object to enable one holder or body to be used
with any number of differently shaped tools or cutters in such a manner that
operations at present carried out in the lathe by means of solid forged tools may
be carried out with one solid body or cutter bar and one of a number of small
tools or cutters similarly shaped as to their bodies but variously shaped as to
the cutting edges fixed into but easily removeable from the said solid body. It
has for an additional object to enable a workman to quickly set any such tool
or cutter for the time being in the cutter bar or holder at any desired angle to
the work to be operated on without altering the position of the holder on the
slide-rest of the lathe and without altering or in any way interfering with the
height of the cutting edge of the tool. It has also for object to enable the
workman to quickly adjust the edge of the tool to a height suitable for the
work without altering the angle of such tool to the work and without altering
the position of the main body on the slide-rest or disturbing such position in
any way whatsoever.
Such being the nature of my invention I now proceed to describe fully by
means of the accompanying drawings the means by which I carry the same into
effect.
In carrying out this invention I make the main body of the tool holder from a
forging or casting preferably of steel and of the shape shewn in Fig. I of the
annexed drawings this drawing representing a perspective view of the main body
denuded of all fittings. A part of it A of suitable length can be fixed in the
tool box of the slide rest in the usual way and upon one end is a projection B
of suitable height length and breadth this projection having cut in it at the
end where it overhangs the part A a groove C of semicircular section. The
boundary a of this groove is not flush with the boundary surface of the part A
which is out of sight in the drawing Fig. I but which corresponds with the
surface and one edge of which is marked c d but is slightly in front of it as
shewn by the dotted lines which mark its position. This is in order to enable
the thick part of the carriage to keep clear of the surface corresponding with b.
In this groove a carriage M in Fig. II which represents a perspective drawing
of the bar the carriage and the arrangement for clamping it together with the
tool is placed and can slide up and down vertically. It can be fixed rigidly at
any part of its sliding surface by a sling E which embraces three sides of the
part B of the main body together with a section of that part of the carriage
which projects beyond the semi-circular groove C in Fig. I. This sling E is
provided with a screw F working in its back part and against the back surface
of the part B which in Fig. I is marked f. By turning this screw F the sling E

page_text: is drawn backwards so that it rigidly clamps the carriage to the part B. For
preference this sling is so made that its outside side surfaces are flush with the
sides of the lower part A of the body as shewn in the drawing Fig. II. It has
sufficient thickness at the hinder part marked g in Fig. II to enable the screw F
to have a working length of at least as many threads as would be contained in
a length equal to its diameter. The pitch of the screw F should be as coarse
as it can be consistently with the other dimensions of the tool, so as to enable
the workman to loosen or tighten the sling on the carriage by turning through
an arc of ninety degrees or thereabout. By constructing it so the screw head
can be fitted with a tommy G which can be left permanently in place. But it
must be so situated that when the carriage is clamped tightly it does not get
in the way of either the tool box or the slide-rest or the work. Its position
therefore when tightened up will be vertical or nearly so.
•
The carriage M is constructed to slide in the cylindrical hole formed by the
semicircular groove C Fig. I and the corresponding groove in the sling, and
carries a tool or cutter V. As it can be raised or lowered by loosening the
sling E which holds it to the main body the tool and consequently its cutting
edge may be adjusted to a height suitable for the work by raising or lowering
the carriage.
In order to enable the workman to adjust the height of the cutter with the
more ease and certainty the upper part of the carriage has cut upon it a screw
preferably of fine pitch this screw being continued for a distance sufficient to
enable the carriage to be drawn up to the full extent of its adjustability and this
screw is fitted with a knurled nut J in Fig. III which represents a vertical
section through the main body A and its projection B and through the sling E.
The diameter of this nut is such that it overlaps the top inside edges of the
sling but not the outside edges so that its lower surface works against the top
part of the outer end of the sling and against the projecting piece B of the
main body. By turning it when the carriage M has been loosened by turning
the screw F the carriage bearing the tool will be drawn up and it may be de-
pressed by unscrewing the nut J and pushing the carriage down. When the
edge of the tool has been brought to the requisite height the carriage is clamped
again by turning the screw F.
As the carriage under the action of the nut would have a tendency to turn
it is provided with a small stud K which runs in a groove L cut in the back of
the semicircular groove C (Fig. I) in which the carriage slides this groove being
marked Lin Figs. III and I in which latter it is dotted.
To enable the cutter to be swivelled and fixed at any angle to the work the
carriage is made in three pieces and is shewn enlarged in section in Fig. IV.
The main piece M is of such outside diameter as will enable it to be securely
clamped in the main body by the clamp as already described and its lower part
or head N is of such diameter that when in its place in the main body it clears
the surface corresponding with the surface in Fig. I. Through its vertical
axis is bored a hole for the reception of the part 0 which is the second piece of
the carriage. This hole is enlarged in the head N as to take the part Q of the
part and this part should fit it exactly and be at least one diameter in length.
The piece O which fits in the axial hole of M is provided at its upper end with a
screw and this screw is fitted with a nut R such nut abutting on the top surface
of the part M as in Fig. III where the part of R inside the nut J is shewn
dotted. This nut is only bored and screwed for a part of its length the upper
or solid end which is long enough to project at least half an inch above the top
surface of the nut J being bored through its diameter at right angles to its
axis and fitted with a sliding tommy T.
The head of the piece O is of the same diameter as the head N N of the
piece M and between the bottom surface h j of the latter and the top surface k 1
of the former is inserted a washer S of suitably hardened and tempered steel
which has its surfaces truly parallel with each other and with the surfaces h j k l

page_text: of the two pieces and U. This washer is bored out in the centre to
the part Q.
In the part 0 through a diameter of the head and immediately below the
part Q is pierced a hole P for the reception of the tool. It is of sectional shape
similar to the sectional shape of the steel from which the cutters are made and
may be square or round or elliptical or rhomboidal in section. But I prefer
to make it of oblong section the major axis of which is vertical and twice as long
as the minor axis which is horizontal. In any case however the top boundary m n
of the hole must be in the same plane as the top surface k 1 of the head of the
piece 0.
If now a cutter made from steel which is of such sectional shape that it fits the
hole P be thrust into that hole its top surface will abut upon the bottom sur-
face of the washer S as shewn in Fig. V, this being a side elevation of the
carriage and tool but denuded of the knurled nut J of Fig. III. The cutter
or tool is marked V and its top surface o pabuts on the lower surface of the
washer S and the bottom surface of the tool q r rests on the bottom boundary
of the hole P. If the nut R be screwed up it will clamp the tool firmly against
the lower surface of the washer S which takes the upward thrust at the back
end of the tool V and thus obviates any tendency which the tool would have
to dent or swell the metal on the under surface hj of the piece N when under
pressure from work if it abutted directly thereon.
And as the whole piece is free to turn when the nut R is loose the cutter
which is carried in it can be turned through any part of a circle and can be
clamped at any point in the circle by screwing up the nut R again. Also as
the tommy T is free to slide in the nut R it can be withdrawn out of the way
of the work at whatever angle the cutter should happen to be set.
The amount of adjustability of the carriage and consequently of the tool is
regulated by the length of the part M Figs. IV and V in excess of the depth
of the part B of the main body. As in most instances one half inch is sufficient
adjustability the length of the part M should be one half inch more than the
depth of the part B Fig. I plus an allowance of a few threads for the nut J to
bite on when the carriage is at its lowest point or in larged sized tools it should
be made proportionately.
A drawing of the complete cutter bar is shewn in perspective in Fig. VI
where the various parts are marked in those cases where they appear with the
same letters as have been used in describing the detail.
Having now particularly described and ascertained the nature of my said in-
vention and in what manner the same is to be performed I declare that what I
claim is
1. An improved tool holder or cutter bar for use in lathes constructed arranged
or adapted to operate substantially in the manner herein set forth with reference
to the accompanying drawings adapted for use with any one of a number of
lathe tools or cutters which may be differently shaped as to their cutting edges
but are similarly shaped as to their shanks.
2. An improved tool holder or cutter bar for use in lathes constructed substan-
tially in the manner herein set forth with reference to the acccompanying draw-
ings having an adjustable carriage capable of carrying firmly clamped therein
a cutter or tool and capable of being mechanically raised or lowered by means
of a nut acting on a screw thereon and of being firmly clamped to the main
body at any height within the limits of its adjustability in such a manner that
the cutting edge of such tool clamped in the carriage may be quickly and easily
brought to and clamped at the correct height for operating on the work in the
lathe and which can be so raised or lowered without interfering with or altering
in any way the angle at which the tool has been set to the axis of the work in
the lathe and without altering or disturbing in any way the position of the
main body of the tool on the slide rest of the lathe.

page_text: 3. An improved tool holder or cutter bar for use in lathes constructed sub-
stantially as herein described with reference to the accompanying drawings
having an adjustable carriage carrying a tool such carriage being so constructed
that that part of it which carries the tool or cutter can be swivelled and set in such
a manner that the tool makes any desired angle with the axis of the work in the
lathe and firmly and quickly clamped in such position together with the tool
and which can be so swivelled or set without disturbing the height of the cutting
edge of the tool and without altering or disturbing in any way the position of
the main body of the tool holder on the slide rest of the lathe.
4. An improved tool holder or cutter bar for use in lathes constructed sub-
stantially as herein set forth with reference to the accompanying drawings which
is equally well adapted for such general inside and outside lathe work as is
usually performed with solid forged tools.
5. The combination in one tool holder of the principle of adjusting the
height of the cutter without interfering with or disturbing in any way the
position of the main body of the cutter bar on the slide rest of the lathe and
without interfering with or disturbing in any way the angle which the tool
makes with the axis of the work in the lathe with the principle of
adjustability of the angle which the tool makes with the axis of the
work in the lathe without interfering with or disturbing the height of the
cutting edge of such cutter and without altering or disturbing in any way the
position of the main body of the tool-holder on the slide rest of the lathe together
with the principle of a cutter bar adapted for both inside and outside general
turning in the lathe of such kind as is ordinarily performed with solid forged
lathe tools.
Dated this 25th day of April 1899
HANS J. S. CASSAL,
Applicant.