IMPROVEMENTS IN TWIST DRILLS AND IN MEANS OF MANUFACTURING THE SAME, WHICH MEANS ARE ALSO APPLICABLE TO THE MANUFACTURE OF SCREW AUGERS."
Year: 1877

page_text: LETTERS PATENT to Alfred Vincent Newton, of the Office for Patents,
66, Chancery Lane, in the County of Middlesex, Mechanical Draughtsman,
for the Invention of "IMPROVEMENTS IN TWIST DRILLS AND IN MEANS OF
MANUFACTURING THE SAME, WHICH MEANS ARE ALSO APPLICABLE TO THE
MANUFACTURE OF SCREW AUGERS." A communication from abroad by
Christian Frederick Jacobson, of the City and State of New York; George
Erastus Maltby, of Norfolk, in the State of Virginia; and James Charles Jones,
of the City, County, and State of New York, United States of America.
PROVISIONAL SPECIFICATION left by the said Alfred Vincent Newton at
the Office of the Commissioners of Patents on the 30th May 1877.
ALFRED VINCENT NEWTON, of the Office for Patents, 66, Chancery Lane, in the
County of Middlesex, Mechanical Draughtsman. "IMPROVEMENTS IN TWIST DRILLS
AND IN MEANS OF MANUFACTURING THE SAME, WHICH MEANS ARE ALSO APPLICABLE
TO THE MANUFACTURE OF SCREW AUGERS." [A communication from abroad by
Christian Frederick Jacobson, of the City and State of New York; George Erastus
Maltby, of Norfolk, in the State of Virginia; and James Charles Jones, of the City,
County, and State of New York, United States of America.]
One improvement in twist drills relates to the manufacture of such drills with
a varying twist or pitch, that is to say, with the twist diminishing and pitch
increasing from the point towards the back part of the drill, for the purpose of faci-
litating the clearance of the drill in working. In a twist drill having a varying
twist or pitch, and having its grooves of similar transverse sectional form throughout
the whole length of the cutting part of the drill, the grinding of the conical point to
a similar angle to the axis throughout the whole length of the drill would produce a
varying form of the cutting edges of the drill.
The objects of this part of the Invention is to obtain in a twist drill of varying
twist or pitch, when such drill has its point ground always to a given angle with the
axis, a uniform shape of the cutting edges of the lips throughout the whole length,
and to this end this part of the Invention consists in making the grooves of such

page_text: varying transverse sectional form throughout their length, that the point being
always ground to a given angle, the uniform shape of the cutting edges of the lips
will be preserved.
Another improvement, which relates to twist drills having either a uniform or
varying twist or pitch, consists in making the grooves of such drills of such trans-
verse sectional form that the cutting edges of the lips present convex curvatures
instead of straight lines or concave curvatures, as in the twist drills commonly made.
In carrying out the above improvements-in-twist.drills it is proposed generally,
instead of cutting the grooves in spiral form by milling tools, first, to make drill
blanks with straight grooves, and afterwards to twist the said blanks to give them
the spiral form desired, and to finish by grinding the external surfaces of the drills
60 produced.
The improvements in the means of manufacturing twist drills, which may be also
applied to the manufacture of screw augers, relate to the means of twisting the groove
drill or auger blanks after the grooves have been formed in them by rolling between
suitable rolls, or by other suitable means. These improvements consist principally
in a system of spiral sectional dies fitted to a spiral groove in a die holder, and of n
transverse sectional form, to conform more or less nearly to the transverse sectional
form of the grooves in the blank. The blank is twisted by being driven or forced
longitudinally through or into the said dies. The die holder is composed of a hollow
internal body of cylindrical or conical form, in which are provided the spiral grooves
for the reception of the dies, and an external case or sleeve fitted to the exterior of
the said body, and serving to secure the dies in place.
When the body and case or sleeve are of conical form, the dies may be adjusted
by a longitudinal movement of the sleeve or cone to bring them nearer to or further
from the centre of the holder, according to the size of the drill or auger to be pro-
duced, so that more than one size of drill or auger might be twisted by the same set
of dies. The conical form of the holder also provides for the easy releasement.of the
dies by the longitudinal movement of the external case or sleeve when it is desired
to take out one set of dies and substitute for them another, set. This system. of dies
and die holder is applicable, with proper constructions of the dies, to the production
of twist drills or screw augers having either an uniform or varying twist throughout
their length.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent-filed' by,
the said Alfred, Vincent Newton in the Great Seal Patent Office on the.
30th November 1877.
ALFRED VINCENT NEWTON, of the Office for Patents, 66; Chancery Lane, in the
County of Middlesex, Mechanical Draughtsman. “IMPROVEMENTS IN TWIST DRILLS
AND IN MEANS OF MANUFACTURING THE SAME, WHICH MEANS ARE ALSO APPLICABLE
TO THE MANUFACTURE OF SCREW AUGERS." A communication from abroad by.
Christian Frederick Jacobson, of the City and State of New York; George Erastus
Maltby, of Norfolk, in the State of Virginia; and James Charles Jones, of the City
and State of New York, United States of America..
One improvement in twist drills relates to the manufacture of such drills with
a varying twist or pitch, that is to say, with the twist diminishing and pitch
increasing from the point towards the back part of the drill for the purpose of faci-
litating the clearance of the drill in working. In a twist drill having a varying
twist or pitch, and having its grooves of similar transverse sectional form throughout
the whole length of the cutting part of the drill, the grinding of the conical point to
a similar angle to the axis throughout the whole length of the drill would produce a
varying form of the cutting edges of the lips of the drill.
The object of this part of the Invention is to obtain in a twist drill of varying
twist or pitch, when such drill has its point ground always to a given angle with
the axis, a uniform shape of the cutting edges of the lips throughout the whole
length, and to such end this part of the Invention consists in making the grooves
of the drill of such varying transverse sectional form throughout their length, that
on the point of the drill being always ground to a given angle, the uniform shape of
the cutting edges of the lips will be preserved.
Another part of the Invention, so far as it relates to the construction of twist
drills is concerned, is applicable to twist drills, whether the same have a uniform.or
varying twist or pitch, and consists in making the grooves of said drills of such
transverse sectional form that the cutting edges of the lips of the drill present convex
curvatures instead of straight lines or concave curvatures, as in the twist drills.
commonly made. Such convex configuration of the cutting edges of the lips of the
drill is more efficient than either a straight or concave form.
In carrying out the above improvements in twist drills it is proposed generally,
instead of cutting the grooves in spiral form by milling tools, first, to make drill
blanks with straight grooves, and afterwards to twist the said blanks to give them
the spiral form desired, and to finish by grinding the external surfaces of the drill
so produced.
The improvements in the means of manufacturing twist drills, which are also a
part of this Invention, and which improvements are likewise applicable to the
inanufacture of screw augers, relate to the means of twisting the grooved drill or
auger blanks after the grooves have been formed in them by rolling between
suitable rolls, or by other suitable means. These improvements consists principally
in a system of spiral sectional dies fitted to a spiral groove in a die holder, and of a
transverse sectional form, to conform more or less nearly to the transverse sectional
form of the grooves in the blank. The blank is twisted by being driven or forced
longitudinally through or into the said dies. The die holder is composed of a hollow
internal body of cylindrical or conical form, in which are provided the spiral grooves
for the reception of the dies. An external case or sleeve is fitted to the exterior of
said body, and serves to secure the dies in place.
When the body and case or sleeve are of conical form, the dies may be adjusted
by a longitudinal movement of the sleeve, case, or outer cone to bring them nearer
to or further from the centre of the holder, according to the size of the drill or auger
to be produced, so that more than one size of drill or auger may be twisted by the
same set of dies. The conical form of the holder also provides for the easy releasement.
of the dies by the longitudinal movement of the external case or sleeve when it is

page_text: desired to take out one set of dies and substitute for them another, set., This system
of dies and die holder is applicable with proper construction of the dies to the
production of twist drills or screw augers having either a uniform or varying twist
throughout their length.
-
"
3.Having thus specified...the object or objects and nature. of the Invention, its
description will be.proceeded with increference to the accompanying Drawing...
_ Fig. 1 represents.a longitudinal view of a twist drill, constructed in accordance
with one part of the Invention ;, and Figures 2, 3, and 4 are transverse sections of
said drill at different points.in.its length..
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Fig. 5.is.a. transverse. section..of a twist drill, illustrating another part of the
Invention relating to the construction of. the drill and Fig. 6, a transverse section
ofa, drill, having the bottoms of its grooves formed with a centre longitudinal
guiding recess to indicate the proper position of the inner corner of each lip when
guiding, the drill.
1
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I. sir
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Figures 7 and 8 represent longi
longitudinal and front end views respectively of a double
straight grooved drill blank prior to being twisted.
is a partially sectional longitudinal view of a conical die holder fitted with
a series of sectional dies, and having an outer cone, sleeve, or case suitable for pro-
ducing a twist drill, and shewing a drill blank as in the course of being twisted;
Fig: 10 represents a transverse section of the same on the line,
" NJ:
Fig. 11 is a longitudinal section of the spirally slotted die holder detached from its
outer sleeve, cone, or case, and with the dies removed.
Fig. 12 represents a transverse section of the drill blank in its relation with two
of the sectional dies, while being, twisted.
.
2-
'
Referring in the first instance to Figs. 1, 2, 3, and 4 of the Drawing, A represents.
a drill of varying twist or pitch, and in, which the grooves are of such varying
transverse sectional form throughout their length that the point of the drill being
always ground to a given angle, the uniform shape of, the cutting edges of the lips,
will be preserved. Thus Fig. 2 represents a transverse section of the drill taken in
proximity to its point, Fig.,3,a, transverse section thereof taken at or near its
middle; and Fig. 4, a transverse section taken, at, or near the rear end of the drill.
In these Figures a, a, indicate the grooves of the drill of varying transverse sectional
form throughout the length of the, latter, and b, b, the cutting edges of the lips, of
uniform shape when the point of the drill is ground to a given angle relatively with
its axis.
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In Figures 2 and 4 the grooves a, a, are of reverse transverse sectional, form, said
grooves being, gradually transformed in accordance with the increase of twist on
pitch from a convex shape at or near the cutting edges of the lips b, b, at the front.
of the drill to a concave shape at or near the rear thereof, but being, of a reverse
concave-form-intermediately-of-the-front-and-back cutting edges, of the-drill, as-
shewn in Fig. 3. This construction provides for the cutting edges of the lips always
having the same shape when grinding the point of the drill to a given anglo
throughout the whole length,of.the.cutting portion of the latter,, - -, -
.
"
In Fig. 6, which represents-a-transverse-section of a twist drill having either a
uniform or varying. twist or pitch, the grooves a, a, of, the drill are of such trans-
verse sectional form that the cutting edges of the lips b, b, present. convex.
curvatures. instead of straight lines or concave curvatures, as in the twist drills
commonly made.
F
To indicate the proper position of the inner corner of each lip when grinding the
drill, the bottoms of the grooves in the drill are made with, a centre guiding
longitudinal recess of approximately V shape in its transverse section, as shewn at
c, c, in Fig. 6, of the Drawing.
The improvements in the means for making twist drills and. augers will now be
described, reference being had to the several Figures of the Drawing from Figures
7 to 12 inclusive.
A¹ is a drill blank having grooves d, d, rolled, drawn, or otherwise formed length-
wise in it. B is a hollow conical die holder, or body portion thereof, constructed

page_text: with duplicate spiral slots e², e¹, through it in direction of its length. Said spiral
slots may either be regular or irregular, accordingly as it is required to produce a
regular or irregular twist in the drill. This die holder B may be supported and
held from turning by any suitable means, and serves to carry within its slots e, e¹,
a series of sectional discs C, C; these discs form two spiral series, which combined
virtually constitute a single spiral die extending throughout the length of the spiral
slots e, e¹. Said dies are fitted freely or loosely within the slots e, e¹, and are of
irregular length, in conformity with the varying diameter of their conical holder B,
in order that they may project equally within the conical holder relatively to the
axial line of the latter to insure their action upon the drill or auger blank as it is
forced or driven longitudinally through the holder B. Said dies C, C, may be con-
structed with heads ff, which serve to prevent the dies passing wholly through
into the die holder, and form backs against which pressure may be brought to bear
to keep the dies up to their work. This pressure or retention of the dies to their
work may be effected by means of an outer hollow sleeve, case, or cone D, arranged
to enclose the die holder B and its dies C, C, and to be longitudinally adjustable, as,
for instance, by a screw thread g at its one end over or along the die holder B, so
that by turning said case or hollow cone D to the right or to the left, it varies the
distance; the inner or working ends of the dies C, C, may be forced outwards from
the axial line of the die holder to adapt the dies to different diameters of blanks or
different depths of grooves d in the blanks. Such longitudinal adjustment of the
outer cone or case D may also be used by relieving the dies to facilitate the drawing
back or out of the drill after it has been twisted by the dies.
To twist the drill the outer case or cone D is adjusted to retain the dies C, C, at
their proper distance from the axial line of the die holder B when said dies are acting
upon the blank through its grooves d, d. The blank A¹ then having been suitably
heated, is introduced within the forward end of the die holder, and so that the two
opposite forward sectional dies C, C, enter within or fill the straight grooves d,d, of
the blank at the front end of the latter. The blank A¹ is then forced longitudinally
through the die holder in the direction of its axis, thereby causing the several
sectional dies C, C, throughout the length of the die holder successively to be
received within the grooves in the blank A', and so twist the blank in conformity
with the spiral directions of the discs, after which the outer case or cone D may be
slackened to facilitate the extraction of the twist drill from between the dies and
out of the die holder.
Instead of the drill blank being forced through the dies, the latter, by means of
their holder, may be forced over said blank, which of course would be equivalent.
Two sectional dies of increased spiral length may be used for some kinds of work
in place of a greater number of sectional dies, as shewn in the Drawing.
Furthermore, both the die holder and its outer case may be built up in sections
if desired, and need not necessarily be conical so far as the construction of a spiral
die for twisting a drill in the manner described is concerned.
These improvements are applicable to twist drills or augers having either a varying
or a uniform twist or pitch.
Having now set forth the nature of the Invention of "Improvements in Twist
Drills and in Means of Manufacturing the same, which Means are also Applicable to
the Manufacture of Screw Augers, as communicated to me by my foreign corre-
spondent, and explained the manner of carrying the same into effect, I wish it to be
understood that under the above in part recited Letters Patent I claim,―
First. A. twist drill having a varying twist or pitch constructed with its grooves
of a varying transverse sectional form throughout their length, substantially as
described with reference to Figures 1, 2, 3, and 4 of the Drawing, and for the
purpose specified.
Second. A twist drill having its grooves constructed to give convex curvatures to
the cutting edges of the lips of the drill, substantially as described and shewn in
Fig. 5 of the Drawing.
Third. The spirally slotted hollow die holder in combination with two or more

page_text: sectional dies fitted to enter within said slots, essentially as and for the purpose
herein set forth.
Fourth. The combination of an outer and longitudinally adjustable hollow case or
cone D, the spirally slotted hollow die holder B, and the sectional dies C, C, sub-
stantially as specified.
'
In witness whereof, I, the said Alfred Vincent Newton, have hereunto set my
hand and seal, the Twenty-ninth day of November, in the year of our Lord
One-thousand-eight-hundred-and-seventy-seven.