A MACHINE FOR CUTTING SCREW THREADS ON AUGERS, AND FOR TURNING AND PREPARING THE POINTS OF AUGERS PREPARATORY TO CUTTING THE SCREW THREADS THEREON
Year: 1878

page_text: LETTERS PATENT to Peter Mackay, of Glasgow, in the County of Lanark,
"
North Britain, for the Invention of A MACHINE FOR CUTTING SCREW
THREADS ON AUGERS, AND FOR TURNING AND PREPARING THE POINTS OF
AUGERS PREPARATORY TO CUTTING THE SCREW THREADS THEREON."
Sealed the 20th December 1878, and dated the 7th September 1878.
PROVISIONAL SPECIFICATION left by the said Peter Mackay at the Office
of the Commissioners of Patents on the 7th September 1878.
PETER MACKAY, of Glasgow, in the County of Lanark, North Britain. "A
MACHINE FOR CUTTING SCREW THREADS ON AUGERS, AND FOR TURNING AND
PREPARING THE POINTS OF AUGERS PREPARATORY TO CUTTING THE SCREW
THREADS THEREON."
This Invention, which relates principally to a machine for cutting the screw
threads on the points of augers, viz., those screw threads by means of which the
entrance of the auger into the wood wherein a hole is to be bored by the auger is
effected, has for its object to dispense with the manual operation of cutting the said
screw threads up to the present time employed.
The machine constituting the present Invention consists of a headstock fitted
with a hollow mandrel, and carrying a driving pulley, and provided with spur
wheels and pinions after the manner of a back-geared lathe, for the purpose of
changing the speed from fast to slow as required. This mandrel is made hollow for
the purpose of allowing an auger on the point of which the entering threads have
to be cut to be passed through, the mandrel being provided at one end with gripping
jaws for the purpose of holding the auger concentrically with its own axis.
On the bed of the machine on which the aforesaid headstock, mandrel, and
gearing are carried there is also fitted the apparatus by which the entering screw
threads of the auger are cut. This apparatus is capable of being moved backwards
and forwards on the bed, and being fixed thereon in any required position. This
'

page_text: apparatus is fitted with a pair of levers or arms, which are capable of being moved
on their axis, so that their upper extremities may be varied to any required distance
apart. The upper extremity of each of these levers carries a small driving pulley,
to the axis of each of which is fitted a hardened and tempered steel disc, the edges
of which discs are of the form corresponding to the shape of screw thread required
to be cut on the edge of the point of the auger. The edges of the discs are also
formed with cutting teeth, after the manner of the teeth of a file, so that as they
revolve quickly on opposite sides of the slowly-revolving auger point the two
threads required to be formed on the same point are thereby cut, each disc being
placed at the angle corresponding to the inclination of the screw threads, and the
two discs being at opposite sides of the auger being cut, at angles equally but
oppositely inclined.
The hollow mandrel herein-before referred to is provided with changeable screw
matrices, the screw threads on which correspond with the different pitches of screws
required for the different sizes of auger points. The portions of screw nuts attached
to levers, which can be pressed on to or withdrawn from the screw matrices, are also
provided, so that when pressed on the screw matrices attached to the hollow
mandrel, they cause the screw matrix in revolving, and therefore the mandrel,
together with the auger carried therein, to recede at the rate corresponding to the
pitch of the screw thread on the matrix. The front part of the hollow mandrel is
fitted with a collar, within which it revolves, this collar carrying a "shaper" cor-
responding to the form of the auger point, and as the mandrel recedes in the
manner herein-before described, this shaper, acting upon the levers or arms which
carry the revolving cutters, causes them to be closed as the cutting proceeds from
the larger to the smaller end of the auger point, thus ensuring an uniform depth of
screw threads and any desired shape of screwed point over the entire surface of the
point.
The pressure for forcing the cutting discs against the point on which they have
to operate is effected either by a hand lever or by a spring or weights.
Attached to the machine is an apparatus for squaring, turning, and otherwise
preparing the point of the auger preparatory to cutting the screw thereon, which
apparatus is arranged so as to be readily moved out of the way after it has done its
work, so as not to interfere with the working of the screw-cutting apparatus.
The said apparatus consists of a sole plate, on which is mounted a holder carrying
the tool for preparing the point of the auger. When this apparatus is in operation
the tool is brought up to the revolving auger in a direction to form the shoulder of
the
auger at the root of the screw, by the tool holder and sole plate being guided
(in a direction at right angles to the length of the auger) in a groove or grooves in
the bed plate.
When the shoulder has been cut to the proper depth the forward motion of the
tool holder and sole plate is discontinued, and the tool holder has a motion
imparted to it for cutting the point of the auger of the required form. For this
purpose the tool holder is guided in a horizontal plane against a curved guide or
cam piece on the sole plate, by which the tool is caused to move and operate in a
curvilinear course corresponding to the curve which the auger point is required to
have. The curved guide on the sole plate is made capable of removal, that it may
be replaced by guides of different curves as occasion requires.
The movement of the tool holder in the sole plate, and of the sole plate and
holder for bringing them up to their work, may be effected by hand levers, screws,
or other suitable means.
In place of cutting the screw threads on the auger at one operation by means of
two discs mounted and revolving in two arms, the said screw may be cut by means
of one disc on one of the arms.
Where a screw of more than one thread is required to be formed on the auger
the operation will be repeated, the mandrel or one of its attachments being marked
with indications by means of which the bringing back of the auger to the requisite
position for cutting each thread may be ensured. When but one disc is thus used

page_text: the opposite arm or lever may have thereon a revolving cutting tool, by which the
point on the auger will be cut immediately after the cutting of the screw is finished.
The movement of this arm may be effected by the same lever which operates the
arm carrying the screw-cutting disc.
•
By this Invention all the operations are performed successively in the same
machine without the necessity for removing the auger between the operations.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Peter Mackay in the Great Seal Patent Office on the 7th March
1879.
PETER MACKAY, of Glasgow, in the County of Lanark, North Britain. « A
MACHINE FOR CUTTING SCREW THREADS ON AUGERS, AND FOR TURNING AND
PREPARING THE POINTS OF AUGERS PREPARATORY TO CUTTING THE SCREW
THREADS THEREON."
My said Invention relates principally to a machine for cutting the screw threads
on the points of augers, viz., those screw threads by means of which the entrance.
of the auger into the wood or substance wherein a hole is to be bored by the auger
is effected, and my said Invention has for its object to dispense with the manual
operation of cutting the said screw threads.
The said machine may be provided with an attachment by which it is rendered
capable of squaring, turning, and otherwise preparing the end of the auger upon
which the screw is to be cut preparatory to cutting the said screw thereon, which
apparatus is arranged so as to be readily moved out of the way after it has done its
work, so as not to interfere with the operation of the screw-cutting apparatus.
And in order that my said Invention may be properly understood I now proceed
more particularly to set forth the system, mode, or manner in or under which the
same is or may be used or practically carried into effect, reference being had to the
accompanying Drawings, and to the letters and figures marked thereon, that is to
say:
Figure 1 represents in plan a machine and its attachments constructed according
to my Invention, and Figure 2 represents the same in side elevation. A shaft A,
constituting a hollow mandrel, is mounted to turn in bearings a upon the framing B
of the machine. The upper part only of the said framing is shewn in the Drawings,
but it will be understood that the machine is mounted at such a distance above the
floor as will be convenient for operation. The shaft or mandrel A is hollow to
admit the auger to be operated upon to be passed into it, so that the end to be
shaped, and upon which the screw is to be cut, projects the requisite distance from
one end of the said shaft or mandrel, the said shaft or mandrel being at this end
provided with gripping jaws a¹, a¹, for the purpose of holding the auger concen-
trically and in line with the centre of the mandrel.
The jaws may be constructed and caused to grip in any desired or ordinary way
in which similar parts of lathes are constructed and caused to grip.

page_text: As shewn in the Drawing, the outer sides of the jaws are inclined, their highest
parts being outward, so that as the similarly internally inclined collar a is screwed
forward it presses inwards the said jaws and causes them to grip and retain the
auger firmly in position.
The shaft Cis the driving shaft of the machine. It is mounted in bearings c, c,
and is driven by one or other of the pulleys c', c, which are of different sizes to.
give, or aid in giving, different speeds, and are kept constantly running by bands
from an overhead or other shaft. A clutch between them is attached by a groove
and feather to the shaft C, and the pulleys c¹, c, run loosely upon the said shaft;
according, therefore, as to which pulley the clutch c³ is engaged with, the shaft C is
driven at a greater or less speed. The said shaft C carries a toothed wheel C¹ and
a broad toothed pinion C. The shaft A likewise carries a toothed wheel A³ and a
pinion A. The shaft C is capable of being slidden in its bearings, so that in place
of the toothed wheel C' driving the shaft or mandrel A through the pinion A¹
(whereby a rapid motion is given to the said mandrel), the said "wheel and pinion
are thrown out of gear, and the pinion C2 engages with the wheel A2, and drives the
mandrel at a slower rate. The wheels giving the high speed are in gear when
the end of the auger is being shaped and the entering point formed, and those giving
the lower speed are in gear when the screw is being cut.
At the end of the shaft or mandrel A is a screw matrice d, the pitch of the screw
thread on which corresponds with the pitch of screw thread required to be cut upon
the auger. In proximity to the said screw d, and on either side thereof, are portions:
of screw nuts 'd, the screw of which corresponds with the screw. of the matrice, the
said portions of nuts d¹ being carried by the upper arms of levers d², turning upon
a fulcrum at d³, the said levers being so arranged that when their arms below the
fulcrum dare forced apart the portions of screw nuts d' engage with the screw d,
and cause the said screw, as the shaft or mandrel A is rotated, to travel in the said
portions of nuts, and thereby give a backward longitudinal traverse in its bearings
to the shaft or mandrel A.
The matrice d'and portions of screw nuts d' are made removeable, so that various
pitches of screws may be substituted as required.
:
A spring may be placed between the lovers ², tending to force them away from
the matrice. The lower arms of the levers are forced apart by an inclined plane e
upon a bar e sliding through the standard of one of the bearings a. This bar e is
attached by the rod e³ to a bar e sliding in two of the standards of the bearings,
this bar carrying an embracing piece engaging with the collar c' on the shaft C,
and the said bar is also attached to the shifter c of the clutch c. The lever F
turns on the framing B upon a pin at f, and its inner end f¹ enters a slot in the
bar e
It will be seen that by moving the handle F in one or other direction it so
moves the bar e that the shaft C is moved longitudinally for engaging the wheels
A¹, C, or A, C, the inclined plane e is forced between the lower ends of the
levers ; and presses the nuts d' into engagement with the matrice d, or the
reverse, and shifts the clutch from the pulley c¹ to that c or the reverse.
Whilst the high speed is given to the mandril A, that is to say, whilst it is not
moving longitudinally, a half collar (which may be on a bar hinged to the opposite
bearing c), not shewn in the Drawings, may be turned down over the shaft A at
the part marked w, so as to form a filling between the bearing a and the back of
the part a², and prevent longitudinal movement of the shaft A.
On the bed of the machine, sliding in dovetail guides therein in line with the
length of the mandrel A, is the apparatus marked Y in Figures 1 and 2, by which
apparatus the entering screw thread or threads and the end point upon the auger
ends are cut. Figures 3 and 4 represent respectively side elevations (taken at right
angles to each other) of this apparatus. It is brought up to. position for its tools
to act upon the auger and is withdrawn from that position by the lever G (Figures 1
and 2), which is jointed and has its fulcrum at g. Passing through the said lever
and the bottom plate of the apparatus Y-is a set screw g', by screwing down which

page_text: to bear upon the bed of the machine; the apparatus can be fixed many position to
which it may be brought.
An adjustable stop g³ (Figure 2) is mounted on the bed of the machine to limit
the motion of the said apparatus, so that it may be brought up to its proper position
for action.
Referring to the large views of the said apparatus Y, Figures 3 and 4, the
foundation plate H has two double standards h, h, for carrying the mechanism of the
apparatus, which consists of two arms or levers J, whose lower parts are bifurcated
and enter slots in the foundation plate H, where they turn upon pins h¹, so that they
can be brought into position for action or out of that position by means of the
lever I, having its fulcrum upon a pin i passing through lugs i' on the upper part
of a guide piece, whose lower part is capable of rising and falling in a slot in the
foundation plate H, to which pin is also attached an arm 2 Turning on pins h³, h²,
passing through the standards h are levers is, their lower ends being attached, that
of the one to the lever I, and the other to the arm . The upper ends of these
levers carry bearing screws to bear upon the upper ends of the levers J to force
them inward when the lever I is raised, this raising forcing the lower ends of the
levers outwards, and therefore the upper ends inwards.
-
As
In bearings in the upper ends of the levers J are the shafts j of cutting discs 1.
and 3, and also upon the said shafts j are pulleys j³ for driving the said discs, which
may be effected by bands from the overhead shaft which drives the shaft C of the
machine. The disc j¹ is for cutting the point upon the tip of the auger, and has a
form on its cutting edge which corresponds with the shape of point required. The
other disc () is for cutting the screw threads on the end, and has a form at its
edge which will cut the required shape of space between the screw threads.
the disc is required to be set at an angle corresponding to the pitch of the screw
to be cut, its bearing is made adjustable, it consisting of a block J', through which
the shaft of that disc passes, the said block being in a slot in its lever J sufficiently
large to allow of its rise and depression at either end by turning on the pin j".
The screws j, j, bear upon the top of this block, and by them it is adjusted to the
required angle and retained in that position. Figure 5 is a longitudinal section,
and Figure 6 a transverse section of this part of the said lever, shewing this
bearing clearly. The end of the bolt j is square, and the washer at the other side
has a similar square. They take into recesses in the lever J large enough to allow
of motion of the centre. Figure 6 shews the bolt head in its recess.
The parts
are fixed in position when set by the nut 77.
As the disc j¹ for cutting the point is required to be brought into action by the
raising of the lever I, whilst the other disc. is not brought into its acting position,
the lever J. of the said disc j' is provided with a filling piece j³, which being brought
down between the screw and the said lever J causes the bringing up of this
disc to position for work without bringing up the other disc j³. The said lever's
are also arranged by the screws being adjusted or otherwise, so that when the
filling piece is withdrawn, the raising of the lever I will bring up the disc j² for
cutting the screw without bringing up the disc j¹.
A spring may be placed between the levers J, J, tending to urge them apart.
With the machine is also shewn combined an apparatus marked X in Figures 1
and 2, this apparatus being for turning, squaring, or cutting the shoulder, and other-
wise preparing the end of the auger preparatory to cutting the screw thereon, the
said apparatus being capable of sliding in the bed of the machine in grooves at
right angles to the length of the mandrel to bring it up to its work. This is effected
by means of the cam K operated by means of a hand wheel k. The axis of this
cam passes through a slot in the foundation plate of the apparatus X, and the cam
lies between, so as to act upon two projections on the said foundation plate. This
slot and these projections are marked respectively k, l, in Figure 1.
.Figures 7 and 8 represent respectively a front elevation and a plan of this
apparatus X. It consists of a foundation plate L-upon a table or sole plate l, on
which is capable of sliding the upper part M carrying. the cutting tool m, for.

page_text: l
preparing the end of the auger preparatory to cutting the screw thereon. The top.
part M is attached to the sole plate by guides ', so as to be capable of sliding.. It
carries between guides m' the tool carrier m², which may be adjusted by rotating
the confined nut m³ upon the screw m³ on the said carrier. The tool m is attached
to the carrier, which attachment may be effected by a bolt m³ passing through the
carrier, and secured by a nut mº; the carrier is secured in place by the bar m². In
the sole plate is a curved slot 13, shewn in the plan of a part of the said sole plate
in Figure 9, and in section of the same and a part of the upper part Min Figure 10.
Projecting from the under side of the sliding part M is a pin m³ provided with an
antifriction roller which runs in the curved slot 12 as the part M is moved upon
the sole plate, whereby the said part M (and consequently the tool m carried
thereby) is moved in a curved course corresponding to the curve of the slot 13, the
guides allowing of this movement. This slot is in a plate, which is fixed in
the sole plate flush therewith, so that it may be removed and replaced by a plate
with other required form of curved slot (72) in it. The movement of the upper
part M is effected by means of a lever N, which is provided with a barrel piece n¹,
by which it is attached to the table or lower part between lugs n² thereon, by a
pin n³ passed therethrough and through the said barrel, part which said pin n³
constitutes the fulcrum of the said lever N. By a similar barrel part n' the said
lever is connected to the upper part M by a pin n passing through lugs no, and
through the said barrel part the motion of the lever is allowed by passing the pin n³
through a bush capable of an up-and-down movement in the barrel part n³, the
said barrel part n not being so long as the space between the lugs no, no, so as to
allow of the motion of the upper part M. in its curved course. Attached to the
bracket 3, so as to have play therein, is a screw capable of being turned by the
hand wheel, and running upon this screw is a nut 16, to which is attached by a
pin joint the forked end of a bar n', whose other end is connected to the upper end
of the lever N. Thus, by rotating the screw the nut 16 (and consequently the
forked end of the bar n') is raised or lowered thereon, and the lever N is moved
in one or other direction, it turning upon its fulcrum at n³, and consequently
moving the upper part M in the one or the other direction and in a curved
course, depending upon the curve of the slot in the sole plate L.
The action of the machine is as follows:-An auger, upon the end of which the
entering screw is to be cut, being placed in the mandrel A, the parts being in the
position, Figures 1 and 2, a rotatory motion of high speed is given to the mandrel A,
and the auger carried thereby. The hand wheel / being operated, the cam K brings
the apparatus X forward to position for work, it coming into contact with such a
point in the outer circumference of the auger that the tool m cuts inwards in a
line at right angles to the length of the auger so as to cut the shoulder (that is the
part marked 1, in Figure 11).
The tool m is preferably formed as shewn in Figure 11, with a cutting
part 2 at such a distance back from the cutting part 3, that the said part 2
makes a cut, at the end of the outer circumference of the body of the auger
truly concentric with the point of the auger. The distance back of the part 2
will be in accordance with the size of the auger required. The said part 2 thus
determines the true size of the auger required. As soon as the said shoulder has
been cut to the requisite depth, the top part (M) of the apparatus X is moved
along in the curved groove in the sole plate 1, and thereby the tool mis
guided in such a course that it cuts and trims the end of the auger that is the
part marked 4 in Figure 11 into the proper shape or curve for the reception of
the screw.
The apparatus is provided with an adjustable stop, which coming against a pro-
jection on the bed plate prevents the tool m.from cutting inwards more deeply than
is required. When the apparatus X has performed the before-mentioned operations
it is moved back by the cam K, and (by means of the lever G) the apparatus Y is
brought into position for work. It is brought to rest in position and fixed in that
position by the set screw g², so that the discs are at the side of the auger end, the

page_text: disc j¹ being opposite the extreme end or point of the auger, and the other disc
being opposite the root of the end part where it joins the shoulder, the said discs
being set or adjusted, the one j¹ such a distance back from the other , as to have
these relative positious. The said discs are both rapidly rotated by the bands passing
over their pulleys 3. The filling piece being depressed and the lever I raised,
the disc jis brought to bear upon the side of the extreme end of the auger and
form the entering point. The lever I is then depressed and the filling piece j³
raised. The half collar which fills the space w (Figures 1 and 2), is then raised
and the lever F moved so as to give longitudinal motion to the shaft C, and engage
the pinion C with the wheel A2 for giving the mandrel a low. speed, and so also
as to force the incline e¹ between the levers d, and cause the portions of screw nuts
to engage with the matrix d, and so also as to shift the clutch c³ from the pulley c¹
to that c², these parts being so relatively arranged as to give simultaneously the
various motions. The lever I of the apparatus Y is raised and the screw cutting
disc brought into contact with the shaped end of the auger at the root thereof,
and by the combined rotatory and longitudinal motions of the mandrel A a screw.
is cut thereon. When the thread is to be a double thread the second thread is now
to be cut for this purpose, by bringing the clutch c³ out of gear with both pulleys
c, c²; the machine is stopped and the mandrel slidden longitudinally back to its
former position, and a half turn being given to it, which may be truly made by
means of indications marked upon the mandrel and one of its attachments, and the
second thread of the double thread is then cut in the same manner as the first.
The screw-cutting disc is guided in a curved course corresponding with the curve
of the augur end by a removeable and interchangeable shaper P, connected to the
collar p upon the mandrel A, and guided in one of the bearings a, this shaper
bearing on an antifriction wheel p₁ on that one of the levers J which carries the
disc, whereby it is guided in the required curve.
In place of using the disc j¹ to cut the point it may be similar to the disc j², and
mounted and set at a corresponding angle in an adjustable bearing and in the
necessary relative position therewith, so that the two threads of double screws may.
be cut by the two discs at one operation. In this case of course each lever J will
bear upon the shaper P.
I do not limit myself to the arrangements of cams and levers which I have
shewn for bringing up the tools X and Y to their work, as other equivalent and
convenient arrangements for this purpose may be adopted. By this Invention all
the operations are performed successively in the same machine without removing
the augur between the operations.
Having now described and particularly ascertained the nature of my said Inven-
tion, and the system, mode, or manner in or under which the same is or may be
used or practically carried into effect, I would observe in conclusion that I do not
limit myself to the precise details of construction herein-before described, and
illustrated in the accompanying Drawings, as the same may be varied without
departing from the nature of my Invention, but what I consider to be novel and
original, and therefore claim as the Invention secured to me by the herein-
before in part recited Letters Patent is,―
First. The arrangement and construction of parts constituting the machine for
turning and preparing the points or ends of augers, and for cutting the entering
screw thread or threads thereon, essentially as herein-before described, and illus-
trated in the accompanying Drawings.
Second. The arrangement and construction of parts constituting the apparatus
(marked X in Figures 1 and 2) for turning and preparing the ends of augers
preparatory to cutting the entering screw thereon, essentially as herein-before des-
cribed, and also further illustrated in Figures 7, 8, 9, and 10, of the accompanying
Drawings.
Third. The arrangement of curved slot (12) and engaging projection for guiding
the upper part (M) of the apparatus X in a curved path corresponding to the

page_text: curve to which the auger end is required to be cut, essentially as herein-before
described, and illustrated in Figures 8, 9, and 10, of the accompanying Drawings.
Fourth. The arrangement or combination of lever and screw for moving the
upper part (M) of the apparatus X upon the sole plate (1), essentially as herein-
before described, and illustrated in Figures 7 and 8 of the accompanying Drawings.
Fifth. The arrangement and construction of parts constituting the apparatus
(marked Y in Figures 1 and 2), for cutting the entering screw thread or threads, or
for cutting both the said threads and the entering point on the ends of augurs,
essentially as herein-before described, and illustrated in Figures 3, 4, 5, 6, and
6A of the accompanying Drawings, in which the essential feature is the revolving
cutting tool or discs.
Sixth. The arrangement for adjusting the angle to which the screw thread
cutting discs are set, essentially as described with reference to Figures 5, 6, 6A of
the accompanying Drawings.
Seventh. The shaper (P) for regulating the depth to which the screw threads are
cut by the discs, the said shaper being combined with the machine, essentially as
herein-before described, and illustrated in Figures 1 and 2 of the accompanying
Drawings.
Eighth. The combination of parts constituting the apparatus for holding and
giving variable rotatory and longitudinal motions to the augers under operation,
that is to say, the machine (essentially as described with reference to Figures 1
and 2) irrespective of the apparatus X and Y.
In witness whereof, I, the said Peter Mackay, have hereunto set my hand and
seal, this Fourth day of March, in the year of our Lord One thousand
eight hundred and seventy-nine.
PETER MACKAY. .(L.S.)