IMPROVEMENTS IN THE MANUFACTURE OF TAPS AND DIES to be as follows:
Year: 1884

page_text: I WILLIAM ROBERT LAKE, of the firm of Haseltine, Lake, and Co, Patent Agents,
Southampton Buildings in the County of Middlesex do hereby declare the nature
of my invention for "IMPROVEMENTS IN THE MANUFACTURE OF TAPS AND DIES
to be as follows:-
"
This invention relates to taps and dies adapted to be turned in either direction
in order to form either a right hand screw-thread or a left hand screw thread.
The improved tap and die may be constructed so as to produce either a screw
thread of square cross section or a screw thread of V-shaped cross section.
The tap may have leading or reaming points as usual. It has cutting teeth
arranged preferably.in but two rows. These rows extend in the direction of the
length of the tap but the teeth themselves extend cross-wise thereof.
Between these rows of teeth are bearing ribs contributing towards centring the
tap with relation to the work. These ribs extend lengthwise of the tap.
The teeth are arranged at distances apart corresponding to the pitch of the
screw-thread, to be produced. The teeth nearest the end of the tap at which the
work is started project slightly, but successivo teeth project farther and farther
until the main part of the tap is reached and there the teeth project to the full
extent of the depth of the screw thread which they are designed to produce.
The teeth of the tap have no "direction," in other words they are not so inclined
that the tap is incapable of being turned in but one direction. The teeth in one
row are, however, opposite the spaces between those of the next row and are
quite narrow, from end to end, hence they will cut an inclined thread or screw-
thread in either direction.
The construction of the die is identical with that of the tap, except that in the
former the interior surface has the various features described, whereas in the latter
these features are on the exterior surface.
The one is merely the reverse of the other in this particular.

page_text: I, WILLIAM ROBERT LAKE, of the firm of Haseltine Lake & Co, Patent
Agents, Southampton Buildings, in the County of Middlesex do hereby declare
the nature of my invention for "IMPROVEMENTS IN THE MANUFACTURE OF TAPS
AND DIES" 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 taps and dies adapted to be turned in either direction
in order to form either right hand screw threads or left hand screw threads.
The improved taps and dies-may-be-constructed-so-as-to-produco either screw-
threads of square cross section or screw threads of V shaped cross section.
The tap may have leading or reaming points as usual. It has cutting teeth
arranged preferably in but two rows. These rows will extend in the direction of
the length of the tap but the teeth themselves will extend crosswise thereof
Intermediate of these rows of teeth are bearing ribs contributing towards centering
the tap with relation to the work. They extend lengthwise of the tap.
The teeth are arranged at distances apart corresponding to the pitch of the screw-
thread to be produced. The teeth nearest the end of the tap at which the work is
started project slightly, but successive teeth project farther and farther until the
main part of the top is reached and there the teeth project to the full extent of the
depth of the screw thread which they are designed to produce.
The teeth of the tap have no direction. In other words they are not so inclined
that the tap is incapable of being turned in but one direction. The teeth in one
row are, however opposite the spaces between those of the next row and are quite
narrow, from end to end, hence they will cut an inclined thread or screw-thread in
either direction.
The construction of the die is identical with that of the tap except that in the
former the interior surface has the various features described, whereas in the latter
these features are on the exterior surface. The one is merely the reverse of the
other in this particular.
In the accompanying drawing Figure 1 is a side view of a tap embodying my
improvement, Figure 2 is a side view thereof looking at it from a different position;
Figure 3 is a transverse section of the same taken on the line xx Figure 1; Figure 4
is a transverse section taken on the line y, y, Figure 1; Figure 5 is a side view of
a tap of modified fort; Figure 6 is a side view of this tap looking at it from a
different position; Figure 7 is a transverse section taken at the plane of the dotted
line gure 5; Figure 8 is a transverse section taken on the plane of the dotted
line u, u Figure 5; Figure 9 is a transverse section of a tap of modified form
embodying my improvement; Figure 10 is a transverse section of a die embodying
my improvement; and Figure 11 is a sectional view of this die taken in a plane
at right angles to Figure 10. Similar letters of reference designate corresponding
parts in all the figures.

page_text: In Figures 1, 2, 3 and 4 I have shown a tap adapted to cut a square thread As
shown it has leading or reaming points a. It is also provided with cutting teeth q
arranged in two rows extending in the direction of the axis of the tap. Inter-
mediate of these rows of teeth are bearing ribs c also extending in the direction of
the axis of the tap. I have shown but two of these ribs.
The teeth in each row are arranged at distances apart corresponding to the pitch
of the screw-thread to be produced. The teeth near the leading points a project
but slightly, but the next teeth project successively more and more until those
nearest the shank e of the tap project the full extent of the screw-thread to be
cut. The sides of the teeth which are in planes extending approximately
lengthwise of the tap converge outwardly so that the teeth taper in radial
directions. The intermediate sides of said teeth which extend transversely to
the length of the tap, are perpendicular to the axis of the tap. At the junction
of the sides which are in planes extending approximately lengthwise of the tap
with the intermediate sides which extend transversely to the length of the tap
cutting edges are formed. The outer extremities of the teeth owing to the outward
taper of the teeth also form cutting edges. The teeth at their bases are of such
extent transversely to the length of the tap that they will not give direction to the
tap so that it will turn one way only. The teeth at their outer extremities have
as great an extent in the direction of the length of the tap as the teeth have in
that direction at their bases. The teeth in one row are not arranged in line with
those of the other row but in intermediate positions.
Owing to the short extent of the teeth transversely to the length of the tap and
the relative arrangement of the two rows, the tap may be turned in reverse
directions so as to cut screw threads running in different directions.
The bearing ribs c do not extend farther from the axis of the tap than the bases
of the teeth b hence they will impinge against the edge of the thread cut.
The teeth of the tap may be formed by cutting a screw thread upon the tap and
then removing the portion of the tap where the thread is not wanted. They aro
not necessarily formed in this manner but I have found this a convenient way to
space them as thereby the work of laying the teeth is facilitated. The teeth are so
short in a direction transverse to the length of the tap body that the incline which
they have owing to the marking of them in the manner described is immaterial
especially as this incline is not appreciable at the extremities of the teeth or
portions farthest from the axis of the tap body which is the portion of the teeth
forming their initial cutting points or edges.
In Figures 5, 6, 7, and 8 I have shown a tap adapted to cut a V-shaped thread
It is like the tap before described except that the teeth taper outwards from their
bases on all four sides.
In Figure 9 I have shown a tap in which the rows of teeth b and the bearing
ribs c are made separate from the body of the tap and dovetailed into the same.
The rows of teeth may be adjusted lengthwise relatively to each other in this
example of the improvement.
In Figure 10 and 11 I have shown a die having in its interior teeth b and
bearing ribs c. As these teeth are designed for cutting a V-screw thread they
correspond with the teeth of the tap which is illustrated in Figures 5, 6, 7, and 8.
For cutting a square screw-thread the teeth would be made to correspond with
the teeth of the tap shown in Figures 1, 2, 3 and 4. There will preferably be
leading points a in either case.
I do not wish to be confined to the use of but two rows of teeth as more than
two rows may be used.
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
A tap or a die having rows of teeth so disposed that the teeth in one row will
alternate with those in the adjacent row or rows the teeth being so constructed

page_text: that they will taper radially or in other words in the direction of their projection
and that they will have so short an extent in a direction transverse to the length
of the tap or the die that the tap or the die may be rotated to the right or the left
for the purpose of cutting a screw thread in either direction substantially as
specified.
Dated this 30th dev of Donamba^- 1001
HASELTINE, LAKE & Co.,
For the Applicant.