Improvements in Taps for Forming Screw Threads in Holes."
Year: 1896

page_text: Date of Application, 19th June, 1896
Complete Specification Left. 18th Mar.. 1897-Accepted, 24th Apr., 1897
Date of Application, 19th June, 1896
Complete Specification Left. 18th Mar.. 1897-Accepted, 24th Apr., 1897
PROVISIONAL SPECIFICATION.
Improvements in Taps for Forming Screw Threads in Holes."
I, WALTER PAYTON of 138 Sheen Road Richmond in the County of Surrey,
Engineer, do hereby declare the nature of this invention to be as follows:-
This invention relates to taps for forming, screw threads in holes and it consists
in constructing the dies or thread forming portions of such taps and the shanks by
which they are operated in separate parts arranged and fitted together so as to
allow of the dies being readily connected to and disconnected from the shanks for
the purpose of changing them."
Also in constructing the dies in a way that will enable them to form the threads
by graduated successive cuts parallel with the axis of the taps and in provi ling the
dies' with guide pieces to enable them to be more accurately centred in the holes
when starting the thread.
In carrying this invention into effect the dies are constructed cylindrically, and
have their centres bored out and their circumferences formed into screw threads
crossed by clearance grooves of any usual kind. The dies for a hole of any given
size may be of any number above one as the dimensions of the thread to be cut
may determine but whatever their number may be each successive die of a series
has its diameter increased in a manner and to an extent that will allow the work
of cutting an entire thread to be divided as equally as possible between the whole
series.
The threads of any series of, dies may be of the same sectional figure or their
figures and dimensions may be made variable as will best suit the kind of metal in
which the threads have to be cut and the dies have their forward or entering ends
tapered for a short distance.
The shanks for operating the dies have one of their ends fitted into the holes
bored in the dies and their other ends squared or otherwise formed so as to
enable them to be rotated by any suitable hand working wrench or by any
kind of machine tapper or other description of tapping tools. The shanks are
provided with carriers which are made to act against lugs formed on the back
ends of the dies in order that the shanks may compel the dies to rotate with
them.
The dies may be secured upon the shanks by any suitable form of catch but
for this purpose it is preferred to form the carriers of the shanks with projections
fitting into notches cut in the lugs of the dies.
One shank will suffice for all the dies of a series and such shank may also be
used for dies of several sizes and kinds. The lower ends of the holes in the dies
are screwed and have fitted into them cylindrical guide pieces of a diameter equal
to the sizes of the holes required to be tapped the object of such guide pieces being
to ensure the starting of the threads concentrically with the holes and keep them
truly in the line of their axes when the thread is being cut.
Dated this 19th dox of Tune 1806
WALTER PAYTON.

page_text: COMPLETE SPECIFICATION.
Improvements in Taps for Forming Screw Threads in Holes.
1, WALTER PAYTON of 138 Sheen Road Richmond in the County of Surrey
Engineer do hereby declare,the nature of this invention and in what manner the
same is to be performed, to be particularly described and ascertained in and by the
following statement,
ment, reference being had to the accompanying sheet of drawings
on which:
Fig. 1 shows the several parts of the tap secured together and ready for tapping
a hole-by hand.
Figs. 7 and 8 show the ends of the tap in plan.
Fig. 2 is a similar elevation of the tap arranged for used in Payton's machine
tapper patented in 1893.No. 3175 but having the die or cutting part of the tap in
section.
Fig. 3 is an elevation of the driving shank & Fig. 2.
Figs. 4-5 show the two ends of the same in plan.
Fig. 6 is a section of the shank on line A Fig. 3, and
Fig. 9 shows the die a in plan on line B Figs. 1, 2.
The die a is constructed of tempered cast steel and has its centre bored out at a¹.
Its exterior is cylindrical, and has formed upon it the screw-thread the tap is
required to cut. The threaded part of the die is of equal diameter from end to
end but a portion of the thread at the lower end of the die is turned off at an angle
as shown at e Figs. 1, 2. The upper end of the dié has the thread turned off it,
and is formed into the lug a which is undercut so as to form the recess as The
driving shank is made cylindrical at b so as to fit the bored out part a¹ of the
die a.
The shank is also cut away at 2 so as to allow it to pass down beside
the lug a of' the die' a and it has a recess cut in it at so as to form a projection
at and this is done in such a way that when the shank is placed in the die a and
turned through a short distance its projection 64 will engage in the recess a³.in
the die a in the manner shown by Fig. 1, and thereby lock the shank and die
together.
•
The upper end of the shank is shown squared in Fig. 1, so that it may be
turned by an ordinary hand wrench and in Figs. 2, 3, it is shown as arranged for.
use in Payton's machine tapper."
"It
may however
any other means.
be made in any other way that will adapt it for being turned by
The bored out part a' of the die a has its lower end threaded as shown in Fig. 2,
and has fitted to it the removéable guide piece d the enlarged part of which is
made cylindrical and is fitted to the hole in which the thread has to be cut and the
purpose of the guide piece is to truly centre the tap in the hole and enable it to
more correctly and readily start the cutting of the thread.
The dies have their, threads cut away longitudinally in three or more places so
as to form cutting edges and clearance spaces as shown in the figures and the
cutting of a thread is entirely done by the tapered lower ends of the dies the
upper parallel part of them serving only as guides, and when the thread is cut by
two or more dies the diameters of. a set of such dies are increassed successively so
as to allow of the work of cutting the whole thread being distributed as equally as
possible between them:"
The manner of doing this will obviously vary with the kind of thread, but when'.
a Whitworth thread has to be cut its depth may be divided into ten equal parts
and the diameters of 'the dies be so arranged that in the case of two being used,
the first die shall cut eight of such parts and the second the other two. When
three dies are used the first shall cut six, the second three, and the third one of

page_text: such parts, and when four dies are employed, the first shall cut four, the second
three, the third two and the fourth one of such ten parts.
Having now particularly described and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed I declare that what I
claim is-
1st. The construction and arrangement of taps for forming screw threads in
holes in three parts combined and secured together in the manner and for the
purposes herein described and illustrated by the drawings hereunto annexed.
2nd. The construction of dies for forming screw threads in holes in series, so
that dies of increassing diameters may divide the cutting of a whole thread
approximately equally between them in the manner herein described and illustrated
by the drawings hereunto annexed.
በር
WALTER PAYTON.