Year: 1889

page_text: Date of Application, 18th Apr., 1889
Specification Accepted, 25th May, 1889
We DAVID MUCKLEY of 1 Crank Hall Lane, Fitter & ALBERT EDWARD PRITCHARD
Tube Manufacturer both of Wednesbury in the County of Stafford do hereby declare
the nature of our said invention and in what manner the same is to be performed, to
be particularly described and ascertained in and. by the following statement :-
Our invention has for its object improvements in screw dies which effect a great
saving upon those at present in use inasmuch as they can be made to answer the
purpose of a considerable number of dies in one by simply adjusting the same to
the size required and there is also a great saving in master taps required as for
instance a three inch master tap will make a die capable of any intern.ediate adjust-
ment to sizes ranging between say two and a half inches and four inches. Our dies
are also capable of cutting not only the screw threads on tubes but on ordinary
coarse thread upon solid bars or shafts. In solid dies the smiths work is consider-
able and after such is worn he has to knock in the sides so as to make them smaller
which often spoils or nearly spoils the die besides being an expensive process. Now
our dies avoid all these difficulties.
In order that our invention may be clearly understood and more easily carried
into practice we have appended hereunto a double sized sheet of drawings upon
which we have illustrated a die made according to our invention but we do not tie
ourselves to the exact details shewn the views being simply given to make known the
principle thereof.
Figure 1. is a front or face view of one of our screw dies complete and ready to
be mounted either in a die holder or in a revolving chuck as to whether the die is
stationary or revolving for either of which purposes the die is quite suitable.
Figure 2. is a back view of the same die shewing the mode in which the casing
is constructed in two parts so as to facilitate the fitting up of the parts.
Figure 3 is a front view similar to the one shewn by Figure 1 but with the setting
ring D removed and a piece of the locking ring broken away to shew how the
Cutters E are fixed in the casing.
Figure 4. is a cross section of Figure 1 shewing the various parts as they come
together inside the casing.

page_text: Figure 5. is an enlarged view of one of the Cutters E.
Figure 6. is a modification of the locking ring C shewing a supplemental ring e
which may be composed of lead or other yielding substance such as timber to adjust
itself to the top e¹ of the cutters E which are roughed to allow the lead or other
substance to penetrate therein and so lock them from any movement when once set
correctly.
Figure 7. is a broken off enlarged view of the front of the cutters E so as to shew
it more clearly.
The cutters E are all made separately from a dovetail or other piece of metal and
are the only parts which must be of such metal as to be capable of receiving a cutting
edge. The box or casing A is formed with a shoulder a¹ to receive the part or ring B
in which the dovetail recesses b' are cut to receive the cutters E. This ring B by
being made separate from A allows the recesses 61 to be shaped out by a shaping
machine or other tool. Each cutter has an inclined end. e upon which the inclined
face d of the annular ring D bears so that as the ring D is screwed down by means
of the notches d² in its edge the cutters E are forced forwards towards the centre
of the die thus making the screw die smaller. When the cutters E are properly
adjusted to size by the ring D the locking ring C is screwed down upon them to
fasten them firmly against shaking and the nut d³ is also screwed down to lock the
ring D against turning.
The front ends e of the cutters E are cut by the master die with any suitable
thread required.
It will be obvious that the ring 1 may be set with set screws instead of being
tapped into A as shewn and the ring may have a soft lead or other face so as to
hold the cutters better. The casings A and B may be made from cast or wrought
iron or from steel cast or wrought as well as the rings C or D, in fact any suitable
metal may be used but I prefer to cast, the parts A, B and D in steel to save forging
and to ensure lightness. By these dies we can screw several sizes without removing
the die from the machine.
We thus effect an economy in every respect.
Having now particularly described and ascertained the nature of our said inven-
tion and in what manner the same is to be performed we declare that what we
claim is :-
The improvements in screw dies having a number of cutters E set in a casing so as
to be adjustable substantially as herein set forth and as shewn upon the drawings.
xpi
GEORGE BARKER,
77, Colmore Row, Birmingham,
Agent for Applicants.
GEORGE BARKER,
77, Colmore Row, Birmingham,
Agent for Applicants.