Improvements in Lathe Tools.
Year: 1897

page_text: Date of Application, 2nd Sept., 1897
Complete Specification Left, 2nd June, 1898-Accepted, 2nd July, 1898
Improvements in Lathe Tools.
I, WILHELM VON PITTLER, of 144, High Holborn, in the County of London,
Engineer, do hereby declare the nature of this invention to be as follows:-
This invention relates to improvements in lathe tools and has for its object to
so construct such tools that their operative edges or extremities can be restored
to their original shape by a simpler grinding operation than is usually required
with lathe tools.
According to the said invention I form the tool with an annular or spiral ridge,
edge or flange so shaped that it corresponds in section to the desired shape of
the cutting edge. A recess or cavity is formed in the tool into which a grinding
disc or wheel can enter so as to grind the flat end of the spiral ridge or flange
and thus renew the cutting edge thereof, without requiring the grinding wheel
to follow the contour of the cutting edge.
One form of tool constructed according to this invention is provided with a stem
or shank whereby it can be secured in the tool holes provided in the head of the
lathe, and this stem carries at its forward end, a suitable head, which may if
desired be separately fixed upon or in the said stem. The head is annular or
rather is provided with a flange, the forward edge of which is of any desired shape
in cross section according to the shape of the cutting edge required. The flange
has a recess or cavity for the purpose aforesaid and is wider at one end than at the
other. Its forward edge therefore forms a spiral, which gradually recedes from
the cutting edge, and the inclination of which is varied according to the kind
of work the tool is to perform.
By thus constructing the tool it is possible to re-grind the tool say until more
than three-fourths of the flange of the head has been ground away.
In some cases the flange may, instead of forming a single spiral, have two or
more spiral portions formed in it, there being a recess or cavity at the wider end
of each spiral portion to admit a grinding disc. Each of these spiral portions
thus forms a cutting edge.
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C.,
Agents for the Applicant.

page_text: the same is to be performed, to be particularly described and ascertained in and
by the following statement:-
This invention relates to improvements in lathe tools and has for its object to
so construct such tools that their operative edges or extremities can be re-
sharpened, by a simple grinding operation, and will still retain their original
shape.
According to the said invention I form the tool with a helical or spiral flange
or shell, so shaped that the section of its cutting edge corresponds to the desired
form to be given to the work. This spiral flange or shell may be either cylindrical
or "relieved," that is to say either circular or spiral in cross section. A recess
or cavity is formed in the tool into which a grinding disc or wheel can enter so
as to grind the flat end of the spiral ridge or flange and thus renew the cutting
edge thereof, without requiring the grinding wheel to follow the contour of the
cutting edge.
Referring to the accompanying drawings,
Figure is a side view, and,
Figure 2 an end view of one form of tool constructed according to this invention.
Figure 3 shows the said tool at work.
Figure 4 is a view partly in section and partly in elevation illustrating
another form of tool and the manner in which the same acts.
Figure 5 is an end view of the same.
In all these figures a is the flange or shell above referred to, and b is the recess
or cavity to admit the grinding disc or wheel which grinds the said flange without
altering the shape of the cutting edge.
The form of tool illustrated in Figures 1 to 3 is provided with a stem or shank c
whereby it can be secured in the tool holder of the lathe, and this stem carries
at its forward end a suitable head which may if desired be separately fixed upon
or in the said stem. The head, or rather its wall or shell forming the flange a
above referred to, is annular or spiral. The forward edge of this flange is of any
desired shape in cross section according to the shape of the cutting edge required.
The face or forward extremity of this flange is relieved or formed as a spiral
which gradually recedes from the cutting edge, and the inclination of which is
varied according to the kind of work the tool is to perform. The flange is also
"relieved" in cross section, that is to say its cross section is of spiral or scroll
shape, as shown more distinctly in Figure 2; it may however be circular in cross
section.
"
"
It will be seen from these figures that the cutting edge is formed partly on the
face or forward portion of the flange, as at a¹, and partly along the circumferential
portion thereof, as at a³, and it imparts to the work c¹ the internal form shown in
Figure 3. By thus constructing the tool it is possible to re-grind the tool, say,
until more than three fourths of the flange of the head has been ground away.
In some cases the flange may, instead of forming a single spiral, have two or
more spiral portions formed in it, there being a recess or cavity at the wider end
of each spiral portion to admit a grinding disc. Each of these spiral portions
thus fornis a cutting edge.
In the modified construction of tool shown in Figures 4 and 5, the flange a
of the tool has a cutting edge only on its circumferential portion, whilst the
recess b, and consequently the cutting edge, is inclined or spiral. This flange
can be either circular or relieved" in transverse section; and may be concentric
with or eccentric to the axis of the tool.
"
The work is revolved in this case on an axis parallel with the tool, which
latter at the commencement of the cutting operation has its recess towards the
work. A handle d is fitted to the rear end of the tool shank c so that the latter
can be turned on its axis, whereby the portion a³ of the edge is first brought in
contact with the revolving work and then as the tool is turned the point of con-
tact is gradually shifted towards the forward end of the tool. Thus there is never

page_text: more than a small fraction of the edge in contact with the work at any particular
time and undue strains are thereby avoided.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, I declare that what
I claim is:-
1. A lathe tool having a spiral cutting edge formed upon a flange or shell pro-
vided with a recess to admit a grinding disc, substantially as described.
2. A lathe tool having both the face and the side or periphery formed or shaped
substantially as described and for the purposes specified.
3. Lathe tools constructed and operating substantially as described with
reference to the accompanying drawings.
Dated this 2nd day of June 1898
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C.,
Agents for the Applicant.