IMPROVEMENTS IN APPARATUS FOR CUTTING HELICAL GROOVES IN TWIST-DRILLS, RIMERS, SCREW-TAPS AND SIMILAR ARTICLES A com
Year: 1882

page_text: LETTERS PATENT to Herbert John Haddan, of Kensington, Middlesex for
an invention of IMPROVEMENTS IN APPARATUS FOR CUTTING HELICAL GROOVES
IN TWIST-DRILLS, RIMERS, SCREW-TAPS AND SIMILAR ARTICLES A com-
munication to him from abroad by Johann Martignoni, of Bockenheim, near
PROVISIONAL SPECIFICATION left by the said Herbert John Haddan at the
Office of the Commissioners of Patents on the 17th July 1882.
HERBERT JOHN HADDAN, of Kensington, Middlesex, IMPROVEMENTS IN
APPARATUS FOR CUTTING HELICAL GROOVES IN TWIST DRILLS, RIMERS, SCREW-
TAPS AND SIMILAR ARTICLES, & communication to me from abroad by Johann
Martignoni, of Bockenheim, near Frankfurt on the Main, Germany,
This invention has for its object to cut helical grooves in twist drills and similar
objects by means of mechanism which can be easily applied to a lathe.
This is effected by mounting the article to be cut on the slide of the lathe and
producing a simultaneous longitudinal and rotary motion of the same, while the
cutting or milling tool is fixed to the mandril.
The twist drill or other article to be operated upon is held across the lathe
between two points one of which is movable by means of three bevol wheels, a
horizontal shaft, a toothed pinion and a stationary rack, arranged as follows: The
spindle or shaft whose point holds and turns the article on its axis is movable in a
bearing attached to the slide, and carries at its opposite end a bevel wheel gearing
into two other bevel wheels mounted on opposite sides of the first bevel wheel on
a horizontal driving shaft which also carries the toothed pinion. Either one or
the other of the two bevel wheels mounted on the driving shaft may be fixed while
the other turns loose, in order to produce at will either a right or left hand helical
groove. By turning the crank which moves the cross slide, the toothed pinion
travels over the stationary rack perpendicularly to the bed of the lathe, thereby
turning the driving shaft and the article mounted on the cross slide.
The cutting
or milling tool has the shape of a cylinder with a rounded end and has a diameter
equal to the width of the groove to be cut, and two oblique planes or faces are cut
on opposite sides of the cylinder, so as to produce the necessary cutting edges.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Herbert John Haddan in the Great Seal Patent Office on the
17th January 1883.
HERBERT JOHN HADDAN, of Kensington, Middlesex "IMPROVEMENTS IN
APPARATUS FOR CUTTING HELICAL GROOVES IN TWIST-DRILLS, RIMERS, SCREW-
TAPS AND SIMILAR ARTICLES," a communication to me from abroad by Johann
Martignoni, of Bockenheim near Frankfurt on the Main, Germany.
The apparatus which forms the object of this invention serves to cut twist-
drills, rimers, screw taps and similar articles, having helical grooves, and may be
attached to an ordinary lathe.
Its construction will be explained with the aid of the accompanying drawing,
in which Fig. 1 is a plan of a part of a lathe provided with the attachment, while
Figs. 2 and 3 are respectively a side view and a front view of a cutting tool. The
frame A A of the apparatus is fixed to the upper or cross slide of the lathe. The
frame carries an adjustable screw C and a driver D with triangular extremity
forming a centre between which and the centre of the screw C the piece of work is
mounted. Opposite the piece of work is placed the peculiarly shaped cutter f
secured to the mandril by means of a chuck. The object to be grooved is
approached to the cutter f by turning the handle M of the slide. The required
helix is produced by a slow longitudinal and simultaneous slow rotary motion of
the piece of work by means of the following mechanism. The pin D which serves
as a driver, carries at one extremity a bevel wheel R, and the contiguous end of
the frame A A. forms a forked bearing for the horizontal shaft W, on which are
On the same
mounted the bevel wheels R1 and R2 gearing into the wheel R.
shaft is keyed outside the bearings a spur wheel S which gears into a rack T bolted
to the lathe-bed parallel to the piece of work. If the handle N is turned in order
to move the lathe slide so as to obtain a longitudinal motion of the piece of work,
the pinion S which gears into the stationary rack T is forced to revolve and
transmits this motion to the bevel wheel R by means of one of the bevel-
wheels R and R2 mounted on the shaft W. Thereupon the wheel R turns the
driver D and consequently also the piece of work, on its axis. For cutting a right
hand helical groove the right wheel R2 and for cutting a left hand groove the
left wheel R is screwed fast on its shaft, while the opposite wheel is loosened.
In order to render the helical groove more or less steep, the piece of work must be
turned more rapidly or more slowly, which is effected by changing the spur
wheel S. For producing straight grooves, the screw-cap 8, and subsequently the
pinion S, is detached from the shaft W, while the rack T may or may not be
detached from the lathe. The conical cutters or milling tools hitherto used for
narrow grooves, are soon worn out and cannot be easily redressed. They are
costly, and the shape of their cutting edge prevents their easy working on steel.
To remedy these defects I employ a new shape of cutter, illustrated by Figs 2
and 3. This cutter has a round head K corresponding in shape to the groove to
Two cutting edges are produced on this head by making two oblique
hollow recesses or cuts which owing to their peculiar shape easily attack steel
and can be easily ground into proper shape after having become blunt.
be cut.
Having thus described this invention and the manner in which it may be used,
I claim:
1. The combination of the cross slide of a lathe having the piece of work fixed
thereto, of a driver D with bevel wheel R, bevel wheels R, R and pinion S, a
rack attached to the lathe and gearing into the said pinion, for the purpose of

page_text: producing a rotary motion of the pinion, driver and piece of work, when the cross
slide of the lathe is moved, substantially as described and illustrated.
2. In combination with apparatus for cutting helical grooves, substantially as
described, the special shape or construction of the cutting-tool having cutting edges
formed by two oblique hollow recesses, substantially as described and illustrated.
In Witness whereof I, the said Herbert John Haddan have hereunto set my
hand and seal this seventeenth day of January AD 1883.
H. J. HADDAN
(L.S.)