IMPROVEMENTS IN MACHINES FOR RIFLING GUN AND PISTOL BARRELS
Year: 1881

page_text: LETTERS PATENT to Paul Mauser, of Oberndorf a/ Neckar, in the Kingdom
of Wurttemberg, German Empire, Manufacturer, for an Invention of
IMPROVEMENTS IN MACHINES FOR RIFLING GUN AND PISTOL BARRELS."
"
PROVISIONAL SPECIFICATION left by the said Paul Mauser at the Office
of the Commissioners of Patents on the 24th December 1881.
PAUL MAUSER of Oberndorf a/ Neckar in the Kingdom of Württemberg
German Empire, Manufacturer. "IMPROVEMENTS IN MACHINES FOR RIFLING
GUN AND PISTOL BARRELS,"
The Invention relates to peculiar arrangements and devices on those parts of
machines for rifling gun and pistol barrels which produce the shape and direction
of the rifle cuts, and its object is by means of these arrangements and devices to
produce tapered cut grooves and to make the machine adjustable to such an extent
that any desired twist may be given to the cuts.
It is well known that the inclined position of the ruler or controller guiding the
head to which the cutters are fitted is the reason that the cuts form a regular screw
line of uniform width.
As
Although the ruler or controller can be shifted in the front link, whereby the
twist of the cuts is made large or smaller, yet it remains stationary during the
rifling and therefore the cuts or the grooves become of uniform width.
the object of the new construction is to cut tapered grooves it must be executed in
such way that the head commences the forward cutting at a point which is changed
a trifle from that at which the head in cutting backward had left the rear end, the
breech of the barrel; and that both cuts nearly coincide on the muzzle. The cuts
become therefore wider at the breech, than at the nozzle thereby making them
tapered.
To obtain this action of the head the ruler or controller is raised and lowered
uniformly and automatically at its rear end by the motion of the machine, which
construction forms the main portion of the Invention.

page_text: The ruler or controller which can be turned around a bolt of the front link
remains stationary during the cutting action of the head.
The rear end of the ruler or controller slides on a block which turns round a
bolt of a guide piece. The latter moves up and down in guides or ways in a
bracket mounted under or attached to the bed of the machine for which purpose
the bracket has a slit therein for the said bolt to pass through.
Into the upper part of the guide piece is fitted a piece of hard metal having an
inclined slot therein. The pin of a slide which is moved horizontally backwards
and forwards in ways of a pillar mounted on the bed, can slide in this slot. It
will be readily understood that if the reciprocating movement is given to the slide
the guide piece and with it the rear end of the ruler or controller is lowered or
raised.
Upon a bar moving in bearings and actuated by an eccentric or cam upon the
main shaft of the machine are mounted two tappets which strike the slide
alternately in front and in rear and in that way shift the 'slide forward and
backward.
Supposing the head to be making its backward stroke in the direction
from the muzzle to the breech and the ruler or controller attached to the
guide piece being in its raised position; then the cut in the barrel will be of
uniform width. As soon as the head has left the barrel and while the head travels
about one and a half inches further the front tappet strikes the slide forcing it
back and lowering the end of the ruler or controller. By these means the
inclination of the ruler is slightly diminished and the cutting head turned slightly
to the left by means of the rack which is carried by the ruler or controller. During
the ensuing forward stroke of the head the ruler remains in the assumed position
whereby the twist of the cut becomes a trifle smäller. As at the muzzle the
second cut nearly coincides with the first one, the groove considered as a whole is
tapered wider at the breech than at the muzzle. As soon as the head has left the
muzzle and while it travels about one and a half inches further the rear tappet
forces the slide forward raising the rear end of the ruler or controller into its
original position.
The operation of rifling proceeds in the manner described.
The described apparatus may be employed with old machines or suitably modified
may form part of new machines constructed expressly with regard to the present
Invention.
In order that the machine may be able to rifle barrels with grooves of any taper
the slotted piece is not fastened rigidly to the guide piece but assumes the form
of a circular plate toothed upon its circumference and can be turned round by
means of an endless screw operated by hand. The taper or inclination of the slot
is regulated accordingly and the ruler or controller is consequently moved more or
less whereby the taper of the cut may be varied at will.
The device for lowering and raising the rear end of the ruler or controller may
be modified in the following manner. The above mentioned block upon which
slides the ruler or controller turns on an excentrically arranged wrist pin of the
bolt which turns in a bracket and which is turned backward and forward by a
lever mounted upon the bolt lowering and raising the wrist pin and with it the
rear end of the ruler or controller. The lever is shifted backwards and forwards
by adjustable tappets on the bar moved by the eccentric on the main shaft.
Adjustable stops with spring snaps or bolts fix the lever in its extreme positions.
This arrangement also allows of the cutting of grooves of any taper.

page_text: In the accompanying Drawings similar letters indicate corresponding parts.
Figure 1 is a front view of the essential parts of the new device, Figure 2 is a
rear end view thereof Figure 3 is a plan view thereof Figure 4 is a top and a
front view of the guide. Figure 5 is a vertical section of Figure 2, Figure 6 is a
horizontal section through the rear bolt of the ruler or controller. Figure 7 is a
top view and horizontal section of the guide with the pin slide. Figure 8 is a
front view of the guide arranged to cut grooves of any suitable taper Figure 9 is
a vertical section of this device Figure 10 is a horizontal section of the same
Figure 11 is an clevation of the rear end of the ruler or controller producing the
tapered cut, by means of an eccentric wrist pin. Figure 12 is a vertical section
through the rear bolt of the ruler.
It is well known in the art that the inclined position of the ruler or controller A
in the rifling machines heretofore employed is the reason that the cuts, produced
by cutters fitted in the head which travels backwards and forwards and is
guided by the ruler or controller A form a regular screw line of uniform width.
Although the ruler or controller A can be shifted in the front link B, whereby the
twist of the cuts is made larger or smaller, yet the ruler or controller A remains
stationary during the rifling and the cuts or grooves become of uniform width.
To make tapered cuts or grooves the head must commence the forward eutting
at a point which is changed a trifle from that at which the head in cutting
backward had left the rear end (the breech) of the barrel, but so that both cuts
nearly coincide at the muzzle, By these means the grooves become wider at the
breech, than at the muzzle and are therefore tapered.
To obtain this action of the cutting head the ruler or controller A is raised and
lowered uniformly and automatically at its rear end by the motion of the machine,
which construction forms the main portion of the present Invention. The ruler
or controller A which can be turned around a bolt of the front link B remains
stationary during the cutting action of the head. The rear end of the ruler or
controller A is capable of sliding on the block b which turns round the bolt a, and
is connected in this way to the guide D, the bolt a being fixed to the latter.
guide D moves up and down in guides or ways of the bracket F mounted under
the bed of the machine, which bracket has a slot therein to allow the bolt a to
pass through. Into the upper part of the guide D, is fixed a piece c of hard metal
The

page_text: with an inclined slot therein. The pin d of the slide c which is moved hori-
zontally backwards and forwards in ways of the pillar or bracket F mounted on
the bed G can slide in this slot. It will be readily understood that if a recipro-
cating movement is given to the slide e the guide D and with it the rear end of
the ruler or controller A is lowered or raised. Upon the bar H moving in
bearings and actuated by an eccentric or cam upon the main shaft of the
machine (which parts are not shown in the Drawings) are mounted two tappets f
which strike with their turned up ends the slide e in the front or in the rear and
thereby shift the slide e forward or backward.
The
Supposing the cutting head to be making its backward stroke that is in the
direction from the muzzle to the breech and the ruler or controller A attached to
the guide piece D to be in its high position then the cut in the barrel will be of
uniform width as the position of the ruler or controller A is not changed during
the whole stroke. As soon as the head has left the barrel and while the head
travels about one and a half inches further, the front tappet f strikes the slide c
forcing it back and thereby lowers the end of the ruler or controller A.
inclination of the ruler or controller A is thus Sightly diminished and the cutting
head turned slightly to the left by means of the rack, which is carried by the ruler.
or controller A. This rack and the head are not shown in the Drawing, they being
of well known construction. During the ensuing forward stroke of the head the
ruler or controller A remains in the assumed position whereby the twist of the cut
becomes a trifle smaller. As at the muzzle the second cut nearly coincides with
the first one, the groove considered as a whole is tapered wider at the breech than
at the muzzle.
As soon as the head has left the muzzle and while it travels about one and a
half inches further, the rear tappet f forces the slide e forward raising the rear end
of the ruler or controller A into its original position. The operation of rifling can
now proceed in the manner described.
The apparatus above described is constructed with the object of being applied to
old machines. But it is clear that new machines may be constructed according to
the present Invention the necessary modifications being trifling and familiar to any
mechanical engineer.
In order that the machine may be universal that is to say adapted to rifling
barrels with grooves of any taper which is of great importance the arrangement
shown in Figures 8, 9 and 10 is made use of. The piece c with its slot is not
fastened rigidly to the guide D but assumes the shape of a circular plate e toothed
upon its circumference, and can be turned around by means of an endless sorew h
supported by bearings on the side of D and a spanner key or crank. By turning
the plate e more or less the inclination of its slot is altered accordingly and thereby
the end of the ruler or controller A is more or less raised or lowered.
proportion of the width of the cut groove at the muzzle and at the breech can there-
fore be regulated by a suitable adjustment of the plate e that is to say any required
taper of the cut or groove can be formed by this arrangement.
The
Figures 11 and 12 show a modification of the device for raising and lowering
the rear end of the ruler or controller A. The block b does not turn around the
bolt a but around the wrist pin i made in one piece with the bolt a but arranged
eccentrically to it. The bolt a having its bearing in the bracket E is turned by
the lever D mounted upon a whereby the wrist pin i and with it the rear end of
the ruler or controller A is raised or lowered. The lever D is shifted backwards
and forwards. by the adjustable ring tappets f of the bar H and fixed in its
extreme positions by an adjustable stop with spring snap k.
As the tappets f and the stop devices are made adjustable the whole
arrangement becomes a universal one.
Having thus described the nature of the said Invention and the mode in
which the same may be carried into effect I would have it understood that what
I claim is,
First. In gun and pistol barrel rifling machines the guide D on the rear end of

page_text: the inclined ruler or controller A in combination with the slot c slide e with
pin d and with the tappets of the bar H which is actuated from the main
shaft of the machine working together as described and for the purpose explained.
Second The plate e revolving in the guide D and toothed upon its circum-
ference in combination with the slot c the screw h and the other parts of the
apparatus named in the foregoing claim working as described and for the purpose
explained.
Third. The ruler or controller A operated by the eccentric wrist pin i of
the bolt a and the lever D in combination with the ring-tappets f of the bar H
and an adjustable stop device k and with the other parts of the apparatus
named in the first claim working as described and for the purpose explained.
In witness whereof I the said Paul Mauser have hereunto set my hand
and seal this Nineteenth day of June in the year of our Lord One thousand
eight hundred and eighty two.
PAUL MAUSER. (L.S.)