IMPROVEMENTS IN MACHINERY FOR CUTTING SCREW THREADS, AND FOR THE PRODUCTION OF PLAIN AND FIGURED CIRCULAR SURFACES IN METAL
Year: 1872

page_text: LETTERS PATENT to Joseph Barrow, of the City of Manchester, in the
County of Lancaster, Mechanical Engineer, for the Invention of
"IMPROVEMENTS IN MACHINERY FOR CUTTING SCREW THREADS, AND FOR
THE PRODUCTION OF PLAIN AND FIGURED CIRCULAR SURFACES IN METAL."
Sealed the 18th April 1873, and dated the 29th October 1872.
PROVISIONAL SPECIFICATION left by the said Joseph Barrow at the
Office of the Commissioners of Patents, with his Petition, on the
29th October 1872.
I, JOSEPH BARROW, of the City of Manchester, in the County of
Lancaster, Mechanical Engineer, do hereby declare the nature of the
said Invention for "IMPROVEMENTS IN MACHINERY FOR CUTTING SCREW THREADS,
AND FOR THE PRODUCTION OF PLAIN AND FIGURED CIRCULAR SURFACES IN METAL,"
to be as follows:-
My Invention relates to machinery of that class in which the cutting
tools or dies revolve, and the metal to be operated upon moves in the
direction of its axis, but does not rotate, and consists mainly,
First. In holding the metal upon which an external screw thread
is to be cut between centres, one centre being carried by the travelling.

page_text: part or saddle carrying the vice or gripping apparatus for holding the
work, and the other centre moving concentrically within a hollow
mandril carrying the die holders and their dies.
Secondly. In adjusting the positions of the dic holders simultaneously
by means of a, conical sleeve or tube; or an inclined surface or surfaces
arranged concentrically with the centres carrying the metal to be operated
upon so as to move the die holders with their dies towards or from the
axis of the work, and thereby to adjust their positions simultaneously
and accurately according to the diameter of the piece of metal to be
operated upon, whether the dies be revolving or not.
Thirdly. In the combination in a machine for producing circular,
plain, and figured work of a centre carried by the travelling part or
saddle carrying the vice or gripping apparatus with a centre moving
concentrically within a hollow mandril carrying the tool holders and a
concentric conical sleeve, or tube, or an inclined surface or surfaces
for simultaneously adjusting the positions of the cutting tools.
I prefer to construct the machine with a slide bed and bearings for
carrying a hollow mandril with an enlarged chuck at the front end
containing the die holders. This mandril is made to revolve by suitable
spur or other gearing. Into the chuck are cut radial grooves fitted with
die holders which are formed or provided at their outer ends with
inclined planes or surfaces which fit against the inner surface of a sleeve
or tube made in the form of the frustum of a cone, and into slots cut
into it, the die holders being kept from leaving the inner surface of the
cone by a plate fastened to them and fitting against flattened surfaces
on the outside of the conical sleeve. This conical sleeve is attached
by screws to a circular envelope revolving in a bearing and made to
slide on the hollow mandril by means of a ring and forked lever
actuated by an eccentric shaft and a handle. This end movement
causes the die holders to simultaneously close or open along the radial
grooves of the chuck, carrying with them the dies. These dies have a
serrated face cut upon them by a chasing tool, into which a holding die
fits, which is kept in position by a set screw.
When the dies require recutting they can be advanced forwards to the
required extent. By this adjustment, and as the die steel can be cut at
both ends, I am enabled to fully utilize the steel. For bringing the dies
to a gauge I use a stop screw, against which a corresponding stop in the
envelope is brought to bear by the handle of the eccentric shaft. I

page_text: prefer to use not less than four dies and die holders, though any greater
or less number practicable can be used. I prefer the cutting action of
the dies to be at the line of centres. These dies can be readily changed
or reversed by first bringing back the envelope until their set screws
and holding dies are exposed to view, and this can be done without
taking off the cover plate.
For securing the concentricity of the screw thread with the rest of the
work, I place the work between two centres carried in a frame, one end
forming the holding arrangement for the work, and the other a cross bar,
having in its middle a turned rod passing through the hollow mandril
and carrying the centre. For the purpose of closing or opening these
centres upon the work I use two screws placed apart to clear the driving
wheel keyed on the hollow mandril, which screws are simultaneously
worked by a spur wheel and pinions, and fit two corresponding nuts in
the cross bar.
The holding arrangement I prefer to be two jaws moved by a right
and left hand screw with a collar having a little free end play in the
bearing. These jaws will grip nuts, bolt heads or rods, and are fitted,
in a saddle which is made to slide on the bed of the machine by a
pinion, rack in the bed, and a handle. A centre is fitted in a hole bored
concentric with the hollow mandril.
For tapping nuts I use a tap holder chuck, screwed into a corre-
sponding recess of the hollow mandril, with a collar bearing against the
cover plate, and recessed to carry suitable tap holders. This screwed
recess can be also used to fasten a chuck for holding work to be
tapped that has been previously bored, in which case the tap is held-
between centres.
The process of working is as follows:-For screwing bolts and rods
previously centred, I place them between the centres screwing the latter
together by the spur wheel. The holding jaws are then made to close
on the head of the bolt, the end play of the collar of the screw allowing
for any inequality. The dies are brought to gauge by the stop, and the
work is brought forward by turning the handle of the pinion which
gears with the rack so as to engage the dies, which when required are
expanded by the handle of the eccentric shaft and the work released
without stopping the machine..
By substituting plain cutters for screwed cutters and placing such
work as bolts and rods between centres plain cylinders will result, and

page_text: by substituting figured cutters and closing them upon work fixed
between the centres, corresponding figured work will result.
For screwing black work not centred, the rod that passes through the
hollow mandril may be withdrawn, but even in this case the work
may be better done by first centre punching it and using the above-
described apparatus.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Joseph Barrow in the Great Seal Patent Office
on the 29th April 1873.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOSEPH
BARROW, of the City of Manchester, in the County of Lancaster,
Mechanical Engineer, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Twenty-ninth day of October, in the year
of our Lord One thousand eight hundred and seventy-two, in the thirty-
sixth year of Her reign, did, for Herself, Her heirs and successors, give
and grant unto me, the said Joseph Barrow, Her special license that
I, the said Joseph Barrow, my executors, administrators, and assigns,
or such others as I, the said Joseph Barrow, my executors, adminis-
trators, 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 "IMPROVEMENTS IN MACHINERY
POR CUTTING SCREW THREADS, AND FOR THE PRODUCTION OF PLAIN AND FIGURed
CIRCULAR SURFACES IN METAL," upon the condition (amongst others) that
I, the said Joseph Barrow, 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 Seal Patent Office, within
six calendar months next and immediately after the date of the said
Letters Patent.
NOW KNOW YE, that I, the said Joseph Barrow, do hereby declare
the nature of the said Invention, and in what manner the same is to

page_text: be performed, to be particularly described and ascertained in and by the
following statement thereof, reference being had to the accompanying
Sheet of Drawings, in which the same letters of reference are used to
denote like parts in all the views:-
My Invention relates to machinery of that class in which the cutting
tools or dies revolve and the metal to be operated upon moves in the
direction of its axis, but does not rotate, and consists mainly,--
First. In holding the metal upon which an external screw thread is
to be cut between centres, one centre being carried by the travelling
part or saddle carrying the vice or gripping apparatus for holding the
work, and the other centre moving concentrically within a hollow
mandril carrying the die holders and their dies.
Secondly. In adjusting the positions of the die holders simultaneously
by means of a conical sleeve or tube, or an inclined surface or surfaces
arranged concentrically with the centres carrying the metal to be
operated upon, so as to move the die holders with their dies towards or
from the axis of the work, and thereby to adjust their positions
simultaneously and accurately according to the diameter of the piece of
metal to be operated upon, whether the dies be revolving or not.
Thirdly. In the combination in a machine for producing circular,
plain, and figured work of a centre, carried by the travelling part or
saddle carrying the vice or gripping apparatus with a centre moving
concentrically within a hollow mandril carrying the tool holders, and a.
concentric conical sleeve or tube, or an inclined surface or surfaces for.
simultaneously adjusting the positions of the cutting tools.
Figs. 1 and 2 of the Drawings are sectional plans of the machine.

page_text: with inclined planes or surfaces which fit against the inner surface of a
sleeve or tube e, made in the form of the frustum of a cone, and into slots
cut into it, the die holders being kept from leaving the inner surface of the
cone by plates fastened to them and fitting against flattened surfaces on
the outside of the conical sleeve. This conical sleeve is attached by
screws to a circular envelope e¹ revolving in the bearing b, and made to
slide on the hollow mandril by means of a ring and forked lever/"
actuated by an eccentric strap f2 and a handle ƒ³. This conical sleeve
and envelope are shewn cast together in Figs. 1, 6, and 7, and the die
holders are kept to the inner surfaces of the sleeve by the keeps g
assisted by the springs ; this arrangement I prefer for the smaller
machines as being less in cost and equally effective, though either may
be used. This end movement causes the die holders to simultaneously
close or open along the radial grooves of the chuck carrying with tiem
the dies d. These dies have a serrated face cut upon them by a chasing
tool into which a holding die de fits, which is kept in position by a set

page_text: .
Fig. S shews this form of the dies, and is drawn considerably
more than full size. The object of this form of dies is to enable the
finishing portions of the cutters to correct any roughness of the work
caused by the action of the chamfered or roughing part of the dies.
These dies can be readily changed or reversed by first bringing back
the envelope until their set screws and holding dies are exposed to
view, and this can be done without taking off the cover plate m.
For securing the concentricity of the screw thread with the rest of
the work I place the work between two centres n, n, carried in a frame,
one end forming the holding arrangement for the work, and the other
being a cross bar o, having in its middle a turned rod p, passing through.
the hollow mandril and carrying the centre n. For the purpose of
closing or opening these centres upon the work I use two screwed con-
necting rods placed apart to clear the driving wheel q keyed on the
hollow mandril, which screwed rods are simultaneously worked by a
spur wheel and pinions 7¹ keyed on the rods at the ends, which rods
fit two corresponding nuts in the cross bar o. Another way of doing
this is shewn in Figs. 1, 4, and 5, where the two connecting rods are
plain and slide through the grippers & which set the frame carrying the
two centres n at any required distance apart. The work is tightened
between these centres by the spindle t, revolving nut t, and hand
wheel. When the machine is used for tapping nuts or screwing long
rods, the spindle t is screwed out of the machine.
The holding arrangement I prefer to be two jaws moved by a right
and left hand screw, with a collar having a little free end play by
means of the bearing wo moving in a slot, but which play can be stopped
by tightening the nut and fastening the bearing. These jaws will
grip nuts, bolt heads, or rods, and are fitted in a saddle x, which is
made to slide on the bed of the machine by the pinions y, racks y' in
the bed, and a handle y². A centre n is fixed in a hole bored concentric
with the hollow mandril.
For tapping nuts I use a tap holder chuck screwed into a corresponding
recess of the hollow mandril with a collar bearing against the cover
plate and recessed to carry suitable tap holders. This screwed recessz
can be also used to fasten a chuck for holding work to be tapped that
has been previously bored, in which case the tap is held between
centres.

page_text: The process of working is as follows:-For screwing bolts and rods
previously centred I place them between the centres n, n, screwing
the latter together by the spur wheel r (Fig. 2) or by the revolving
nut and hand wheel. (Fig. 1). The holding jaws are then made
to close on the head of the bolt, the end play of the collar bearing w
of the screw allowing for any inequality of the work.
The dies are brought to gauge by the ring stop j, and the work is
brought forward by turning the handle of the pinion shaft y², which
gears with the racks y', or by any other suitable means so as to engage
the dies, which when required are expanded by the handle of the
eccentric shaft ƒ³, and the work released without stopping the machine.
By substituting plain cutters for screwed cutters, and placing such
work as bolts and rods between centres, plain cylinders will result, and
by substituting figured cutters and closing them upon work fixed
between the centres, corresponding figured work will result.
For screwing black work not centered the rod tha
passes through
the hollow mandril may be withdrawn, but even in this case the work
will be better and more readily done by first centre punching it and
using the above-described apparatus.
The reaction of the strains caused by the cutting dies on the work
being self-contained within the hollow mandril, and taken by a dead
thrust equally against the inclined surfaces of the sleeve, all revolving
concentrically upon the centre carrying the work, and the machine
not being subjected to the vibration caused by revolving irregular
rough work, it is evident that large work, such as bolts, rods, and
joints, with screwed ends, such as are used for marine engines and
now done in slide and screw cutting lathes can be finished with a great
saving of skilled labor in this machine, and where the amount of
material is too great to be removed by one process the automatic
expansion and release of the dies enable it to be done at two or more
times.
Having described my said Invention of "Improvements in Machinery
for Cutting Screw Threads, and for the Production of Plain and Figured
Circular Surfaces in Metal," and having explained the manner of
carrying the same into practical effect, I desire to have it understood
that I do not confine myself to the precise form of inclined surface
shewn in the Drawing for simultaneously moving the dies or cutting

page_text: .
tools towards or from their work, as instead of being in the form of a
conical sleeve of circular cross section, it may, for instance, be in the
shape of a sleeve with irregularly inclined surfaces of a circular or
polygonal cross section, so long as the peculiarity of this part of my
Invention be retained, according to which the surface or surfaces for
moving the die holders is or are inclined in the direction of the axis of
the work, and act in that direction as distinguished from cams or
inclines moving in a plane at right angles to the said axis. I would
also remark that this part of my Invention is applicable to machines.
in which the dies or cutting tools do not revolve as well as to machines
in which the dies or cutting tools do revolve.
And I hereby declare 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, to be as follows:-
First. As respects screwing machines in which the cutting tools or
dies revolve, and the metal to be operated upon moves in the direction
of its axis, but does not rotate, I claim the holding the metal upon
which an external screw thread is to be cut between centres, one centre
being carried by the travelling part or saddle carrying the vice or
gripping apparatus for holding the work, and the other centre moving
concentrically within a hollow mandril carrying the die holders and
their dies, substantially as described.
Secondly. I claim the adjusting the positions of the dic' holders
simultaneously by means of a conical sleeve or tube, or an inclined
surface or surfaces arranged concentrically with the centres carrying
the metal to be operated upon, so as to move the die holders with
their dies towards or from the axis of the work, and thereby to adjust
their positions simultaneously and accurately, according to the diameter
of the piece of metal to be operated upon, whether the dies be revolving
or not, substantially as described.
Thirdly. I claim the combination in a machine for producing circular,
plain, and figured work of a centre carried by the travelling part or
saddle, carrying the vice or gripping apparatus with a centre moving
concentrically within a hollow mandril carrying the tool holders and a
concentric conical sleeve or tube or an inclined surface or surfaces, for
simultaneously adjusting the positions of the cutting tools, substantially
as described.

page_text: Lastly. I claim the mode of setting in the dies for recutting, by
making them with serrated faces, as explained, so that a holding die
kept in position by a set screw fits into any of the grooves or serrations
substantially as described.
In witness whereof, I, the said Joseph Barrow, have hercunto 5
set my hand and seal, this Twenty-fifth day of April, in the year
of our Lord One thousand eight hundred and seventy-three.