AN IMPROVED MACHINE FOR CUTTING THREADS ON SCREWS, BOLTS, AND NUTS, TO THE NUMBER OF FOUR AND MORE AT ONE OPERATION, FROM ONE-QUARTER INCH TO ONE-AND-A-HALF INCH IN DIAMETER AND UPWARDS, PROVIDED WITH SELF-ACTING DISENGAGING ARRANGEMENT OF SCREW-STOCK AND DIES OR TAPS
Year: 1874

page_text: ETTERS PATENT to Henry Conradi, of 7, Lower James Street,
Golden Square, in the County of Middlesex, for the Invention of
"AN IMPROVED MACHINE FOR CUTTING THREADS ON SCREWS, BOLTS, AND NUTS,
TO THE NUMBER OF FOUR AND MORE AT ONE OPERATION, FROM ONE-QUARTER
INCH TO ONE-AND-A-HALF INCH IN DIAMETER AND UPWARDS, PROVIDED WITH
SELF-ACTING DISENGAGING ARRANGEMENT OF SCREW-STOCK AND DIES OR
TAPS." A communication from abroad by Albin Otto Sack, resident
at Cassell, in Hessen, in Germany.
.
PROVISIONAL SPECIFICATION left by the said Henry Conradi at
the Office of the Commissioners of Patents, with his Petition, on
the 1st September 1874.
I, HENRY CONRADI, of 7, Lower James Street, Golden Square, in the
3 County of Middlesex, do hereby declare the nature of the said Inven-
tion for "AN IMPROVED MACHINE FOR CUTTING THREADS ON SCREWS, BOLTS, AND
NUTS, TO THE NUMBER OF FOUR AND MORE AT ONE OPERATION, FROM ONE-QUARTER

page_text: INCH TO ONE-AND-A-HALF INCH IN DIAMETER AND UPWARDS, PROVIDED WITH SELF-
ACTING DISENGAGING ARRANGEMENT OF SCREW-STOCK AND DIES OR TAPS," to be as
follows:
-
Taking into consideration the imperfections existing in the different
systems of screw, bolt, and nut cutting machines now in use, I, Henry
Conradi, of 7, Lower James Street, Golden Square, in the County of
Middlesex, Engineer, as a communication made to me from abroad_by
Albin Otto Sack, resident at Cassell, Hessen, in Germany, Engineer,
have studied out and invented after long experiments the above-named
machine, avoiding the defects of the others and improving mine by
securing its practicability and its simplicity.
I make the machines in eight different sizes, that is to say, for one or
two to four and more shafts for screws, bolts, and nuts, from one-quarter
inch to three-quarter inch, and from one-quarter inch to one-and-a-
half inch in diameter, and also in different forms, so as to be fixed on the
floor or against the wall, thus rendering it casy of adaptation to every
manufacture.
The chief features of my Invention consist of the vertical arrange-
ment of the machine in general, and of the parts in which the screws,
bolts, or nuts to be threaded are imoveably fixed and turn, while at the
same time the screw or die-stock moves downwards or upwards, finishing
the thread at one cut only, and disengaging the die-stock automatically
as soon as the required length of the screw, bolt, or nut is threaded.
The screw or die-stock is fixed in a frame guided by two columns, on
which frame is placed the self-acting disengaging gear of the thread-
cutting arrangement. When the machine is not at work the frame is
lifted into its highest position, and maintained there by means of hooks.
The columns are surrounded by spiral springs, so as to allow the frame
to descend only to a certain depth, having in the case of nut cutting to
perform another operation in addition.
The disengaging arrangement consists of a clamp for holding the jaws
of the screw or die-stock close together, a disengaging pin fixed in the
frame, and an adjustable stop sliding on graduated columns.
The working of the disengaging arrangement is as follows:-In cutting
the screw or bolt the screw or die-stock slides downwards and carries
with it the disengaging pin, which on striking against the stop at the

page_text: proper time exerts a pressure upon the tightening clamp, which on
becoming disengaged allows the dies to be drawn apart by means of
springs, whereupon the threading is suspended.
In the case of nut cutting the clamp and the screw or die-stock are
taken out of the frame and replaced by the nut holder, in which the
different nut dies can be fixed.
Special Description of a Two-shafted Machine for Cutting the Threads
of Screws, Bolts, and Nuts, from a quarter inch to one-and-a-half inch
in Diameter. The shaft a is put in motion by means of the cono
pulley b and a bevel pinion which gears into the bevel wheel d, both this
and another pinion being fixed on to the manishaft. This pinion is in
gear with the driving wheels g, g, which are provided on their upper
surface with clutches, thus allowing of an independent disengagement
of each of the spindles. The levers h, h, are maintained in their.
respective positions by means of the catches i, i. The wheels g, g, run
loose on the spindles k, k, which are made hollow so as to admit of
cutting the thread on very long bolts or screws. The spindles k, k, aro
carried by brackets, while the main shaft is carried by two bearings.
The bottom portions of the brackets 1, 1, have nose shaped projections
cast on, forming a channel for the oil running through the spindles.
The oil running from the cross head and also from the spindles is received
in the oil reservoir A, in which is placed a pump for forcing the cleaned
oil, after it has passed through a strainer up again into the reservoir B
at the top of the machine. This latter is provided with an overflow pipe
for bringing the oil back again into the reservoir A, so that the pump
can be kept in constant action. The pump is worked by an excentric
and its rod. The spindles K, K, have a conical enlargement on the top
to carry the box o, which serves as a holder for the screws or bolts to be
threaded. The box is fixed on to the spindles by means of a cottar and
set screw, and revolves with the spindles. In this box-shaped holder aro
placed the clamps, worked by wheels P, P, and q, and also by set screws,
which are right and left handed. By means of this arrangement the
screws or bolts to be threated are centred and fixed on the holder at the
same time.
It is not necessary to replace the clamps for the different sizes of
screw or bolt heads, but only to introduce packing pieces. The cross
head is somewhat inclined so as to allow of the flow of the oil. In its

page_text: centre is fixed the hollow column u, in which the oil pipes leading to the
reservoir B are placed. The column also serves to strengthen the top
part of the machine. On to the cross head C are fixed the retaining
hooks D, D, which keep the die-stock frame E, E, in its highest position.
While threading screws or bolts the die-stock frames E, E, are provided
with the die-stocks F, F, with the springs G, G, pressing upon it, with
the locking lever H holding the die-stock jaws together, and the dis-
engaging pin J. The locking lever H is so disposed that the nose
pieces H, H, can easily be replaced when worn. When tapping nuts
the die-stock is replaced by the nut holder k, into which the different
nut dies L, L, can be fixed. In both cases the holder. M serves to
maintain the die-stock or the nut holder, as the case may be, in their
respective positions. The dies are fixed on to the bottom of the die-
stock, and are so arranged that the thread is formed at one cut. The
spiral springs V, V', with their collars V¹, V₁, are quite moveable, so that
their positions may be changed as required for regulating the upward
and downward motions of the die-stock frames E, E. The adjustable
stop N slides along the graduated columns Q without being able to turn
round it, so as better to secure the efficient working of the disengaging
arrangement. The columns are graduated so as to facilitate the setting
of the stops at the required distance for determining the length of the
thread to be cutt.
Means are also provided for preventing the screw from beeing threaded
too close up to the head, which might cause fracture to the machine or
stripping of the thread of the screw. The length of the disengaging
pin J is made to suit the position of the disengaging gear so as to effect
the disengagement at the required moment. The springs G, G, are
made easy, so as to allow the jaws of the die-stock to be brought together
with facility. In tapping nuts the box-shaped holder O is removed from
the top of the spindle k by slacking the set screw; the dic-stock is also
taken out of the frame. The top part or. head of the hollow spindle k
is made conical for the purpose of receiving an inserted bearing socket,
and is also provided with a cottar hole to admit of its being driven
out.
In the operation of threading the screws the spiral springs have to be
set deeper, so as to be more compressed by the sliding down of the die-
stock frame. As soon as the tap has passed through the nut, the latter
is released from its holder, falls through, and is left on the top of the

page_text: The
above-named bearing socket, while the die-stock frame is again lifted by
the spiral springs, the tap remaining in the bearing socket.
materials emploied in the construction of he machine are thus allways
used for that purpose in machinery.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Henry Conradi in the Great Scal Patent Office
on the 26th February 1875.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, HENRY
CONRADI, of 7, Lower James Street, Golden Square, County of Mid-
dlesex, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the First day of September, in the year
of our Lord One thousand eight hundred and seventy-four, in the
thirty-seventh year of Her reign, did, for Herself, Her heirs and
successors, give and grant unto me, the said Henry Conradi, Her
special licence that I, the said Henry Conradi, my executors, admini-
strators, and assigns, or such others as I, the said Henry Conradi,
my executors, administrators, and assigns, should at any time agree
with, and no others, from time to time and at all times thereafter
during the term therein expressed, should and lawfully might make,
use, exercise, and vend, within the United Kingdom of Great Britain
and Ireland, the Channel Islands, and Isle of Man, an Invention for
"AN IMPROVED MACHINE FOR CUTTING THREADS ON SCREWS, BOLTS, AND NUTS TO
THE NUMBER OF FOUR AND MORE AT ONE OPERATION, FROM ONE-QUARTER INCH TO
ONE-AND-A-HALF INCH IN DIAMETER AND UPWARDS, PROVIDED WITH SELF-ACTING DIS.
ENGAGING ARRANGEMENT OF SCREW-STOCK AND DIES OR TAPS," upon the con-
dition (amongst others) that I, the said Henry Conradi, my executors
or administrators, by an instrument in writing under my, or their, or
one of their hands and seals, should particularly describe and ascertain
the nature of the said Invention, and in what manner the same was
to be performed, and cause the same to be filed in the Great Scal

page_text: Patent Office within six calendar months next and immediately after
the date of the said Letters Patent.
NOW KNOW YE, that I, the said Henry Conradi, do hereby declare
the nature of my said Invention, and in what manner the same is to be.
performed, to be particularly described and ascertained in and by the
following statement, and notwithstanding the fact that the following
description applies only to the case of a machine with two spindles, tho
description of the arrangement of a machine with from one to four or
more spindles will be similar, repeating only the same arrangement of
working parts and motions required by the use of one spindle or several
as the case may be:
and o.
-
The shaft a is put in motion by means of the cone pulley 6 and the
bevel pinion c, which gears into the bevel wheel d, both this and the
pinion e being fixed on to the main shaft f. The pinion e is in gear
with the driving wheels g, g, which are provided on their upper surface
with clutches, thus allowing of an independent disengagement of cach
of the spindles. The levers h, h, are maintained in their respective
positions by means of the catches i, i. The wheels g, g, run loose on the
spindles k, l, which are made hollow so as to admit of cutting the thread
on very long bolts or screws. The spindles k, k, are carried by the
brackets 1, 1, and m, m, while the main shaft is carried by the bearings n
The bottom portions of the brackets 1, 2, have nosc-shaped
projections cast on, forming a channel for the oil running through tho
spindles. The oil running from the cross head and also from the spindles
is received in the oil reservoir A, in which is placed a pump for forcing
the cleaned oil, after it has passed through a strainer, up again into the
reservoir B at the top of the machine. This latter is provided with an
overflow pipe for bringing the oil back again into the reservoir A, so
that the pump can be kept in constant action. The pump is worked by
the excentrick and its rod x. The spindles k, k, have a conical enlarge-
ment on the top to carry the box-shaped holder O, which serves as a
holder for the screws or bolts to be threaded. The box is fixed on to
the spindles by means of a cottar and set screw, and revolves with the
spindles. In this box-shaped holder are placed the clamps 81, 8, worked
by wheels p', p', and q, and also by set screws 1, ", which are right and
left handed. By means of this arrangement the screws or bolts to be
threaded are centred and fixed in the holder at the same time.
°

page_text: It is not necessary to replace the clamps for the different sizes of
screw or bolt heads, but only to introduce packing pieces t, t. The cross
head is somewhat inclined, so as to allow of the flow of the oil. In its
centre is fixed the hollow column u, in which the oil pipes leading to
the reservoir B are placed. The column also serves to strengthen tho
top part of the machine. On to the cross head C are fixed the retaining
hooks D, D, which keep the dic-stock frame E, E, in its highest position.
While threading screws or bolts the die-stock frames E, E, are provided
with the die-stock F, F, with the springs G, G, pressing upon it, with
the locking lever H holding the die-stock jaws together, and the dis-
engaging pin J. The locking lever H is so disposed that the nose
pieces H₁, H₁, can easily be replaced when worn. When tapping nuts
the dic-stock is replaced by the nut holder K₁, into which the different
nut dies L, L, can be fixed. In both cases the holder M serves to
maintain the die-stock or the nut holder, as the case may be, in their
respective positions. The dies are fixed on to the bottom of the dic-stock,
and are so arranged that the thread is formed at one cut. The spiral
springs V, V, with their collars V₁, V₁, are quite moveable, so that their
positions may be changed as required for regulating the upward and
downward motions of the diestock frames E, E. The adjustable stop N
slides along the columns Q, which are graduated or not, without being
able to turn round it, so as better to secure the efficient working of the
disengaging arrangement. The columns may be graduated so as to
facilitate the setting of the stops at the required distance for determining
the length of the thread to be cut.
Means are also provided for preventing the screw from being threaded
too close up to the head, which might cause fracture to the machine or
stripping of the thread of the screw. The length of the disengaging
pin J is made to suit the position of the disengaging gear, so as to effect
the disengagement at the required time. The springs G, G, are made
casy, so as to allow the jaws of the die-stock to be brought together with
facility. In tapping nuts the box-shaped holder O is removed from tho
top of the spindle k by slacking the set screw Z. The die-stock is also
taken out of the frame. The top part or head of the hollow spindle k is
made conical for the purpose of receiving an inserted bearing socket, and
is also provided with a cottar hole to admit of its being driven out.
In the operation of threading the screws the spiral springs have to be
set deeper so as to be more compressed by the sliding down of the
.

page_text: die-stock frame. As soon as the tap has passed through the nut the
latter is released from its holder, falls through, and is left on the top of
the above-named bearing socket, while the die-stock frame is again
lifted by the spiral springs or by other means, the tap remaining in the
bearing socket.
I have now further to add that each spindle k, can be engaged and
disengaged by the levers h, h, which can be straight or be bend into any
form that may be found most convenient. The main shaft fas well as
the spindles k, k, can be adjusted so as to bear in a horizontal or in an
inclined position. The plates Y, Y,, serving as trays to receive the
turnings or waste made in screw cutting are either placed loose over the
box-shaped holder O or screwed on, thus protecting the dies 81, 81.
The die-stock frame E in which is fixed according to the requirements
of the work the die-stock F or the nut holder K,, instead of by the means
formerly described can as well be maintained in any position by ropes
R, R., or chaines of any suitable material guided over the pulleys 8 ¾¸
to the drum W, while by turning the handle or the crank shaft d itself
the die-stock frame is lowered or raised, and its own motion can at any
moment be stopped by throwing into gear the catch u. The drum
shaft is carried by the plummer blocks T, T, which can be fixed to or
cast on the frame. The oil box R which is fixed to the die-stock frame E
is provided on the inside with a pipe through which the bolts passes as
.it is being cut.
If preferred, instead of the arrangement before described the adjust-
able stop N can be provided at its end with an inclined plan upon which
the disengaging pin J with its end also inclined is brought to bear at the
required time, disengaging the locking lever H and preventing a too
great lowering of the die-stock frame by pressing against it and against
the stops. Each leg of the die-stock is provided with a kind of hand
vice for allowing the dies to be reset in case of their becoming worn by
In tapping nuts the nut dies or taps L, L, are set in or screwed in
in such a manner that a slight motion is allowed in every direction so
as to keep even badly centred nuts in the centre of the tap. The main
disengaging lever G has its bearing on the top plate of the frame, being
provided with an eye-shaped hole in which a pin is fastened to allow
the lever to be fixed in different positions so as to admit of reversing the
gear for left or right-handed motion.
use.

page_text: The general mechanical arrangement of a machine having from one
o four or more spindles corresponds to that which is here described for
machine with two spindles, but the differend working parts and
motions have to be arranged and repeated in each case according to the
umber of spindles employed and in the same manner.
In witness whereof, I, the said Henry Conradi, have hereunto
set my hand and seal, this Twenty-sixth day of February, in
the year of our Lord One thousand eight hundred and seventy-
five.