Improved Steel Taps and Dies.
Year: 1891

page_text: Date of Application, 26th Mar., 1891
Complete Specification Left, 20th May, 1891-Accepted, 12th Dec., 1891
PROVISIONAL SPECIFICATION.
Improved Steel Taps and Dies.
I, JOHN BARTHOLOMEW MCMULLEN of 74 Guide Lane, Hooley Hill, Guide
Bridge, near Manchester, and by calling a Tool Fitter do hereby declare the nature
of this invention to be as follows:-
The tap or die has small cavities cut in, across the threads, at stated distances, in
such a manner as to form a cutting edge in the tap or die. These cavities are cut
so that the tap or die will cut backwards and forwards, thus doing work quicker,
and finishing the thread cleaner. The arrangement of these cavities give an
increased strength to the tap or die over any other sort at present used; they enable
the tap or die to be self lubricating, prevent twisting or cracking in the tempering
process, and have an increased efficiency, generally, over any at present used.
Dated this 24th day of March 1891.
JOHN BARTHOLOMEW MCMULLEN.
COMPLETE SPECIFICATION.
Improved Steel Taps and Dies.
JOHN BARTHOLOMEW MCMULLEN No. 74 Guide Lane Hooley Hill Guide
Bridge near Manchester Tool Fitter &c. 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 :-
Self lubrication by internal and external means.
A small hole drilled up centre of taps.
Cavities cut across the threads at intervals.
Small holes drilled in bottom of cavaties to internal hole in centre, of taps-thus
there are cavaties not " grooves or "Hutes."
One fourth stronger taps.
Double cutting in, and out.
Self lubricating.
"
The taps will bring out their own cuttings.
The taps will not lose the oil.
The taps leave the thread perfectly clean, and not "gall" in any metal, or
compo'.
There is a saving of labour.
Will tap 12 holes, to 8 of other patterns in the same time.
There is improved hardening.
The taps may be sharpened without loss of diameter.
The taps can be used for hand, engine, water, or motive power of any description.
The "dies can be made to any requisite shape, but I prefer square or round
conical holes, in the revolving motion inserted in the stocks to suit the dies.
I further use parallel holes without being confined to any particular shape.
The dies revolve independently of "stock"-(this being a special feature of
my) and are applicable to any other revolving motion (as desired,) I further state
that these "dies" can at any time be made to fit any old, or new stocks on the
rotary principle.
The "dies" are made to cut a full thread at once, or as required by operator, by
physical, or motive power of any kind.
The "dies" & "taps" are perfectly adopted for engineers, gasfitters, or tools of
any description.

page_text: Ting wo represents
"stocks" movcing any way.
The improvement in the taps are cavities, cut to produce strength and self
lubricate and further prevents warping during the process of hardening.
The back of cutting edges of my taps are not filed off, (as other makes) but are
cylindrical to fill a round hole, by this method I increase the strength of the tap
and gain a back cutting edge.
Figures A & B represent a "tap, cut in two ways, one having 6 rows of cavities
and the other four.
Letter
il
"
represents the dies to make the threads correct on bolts or taps &c.
Letter F represents the "die" block:
Letter represents cover gland nut for closing &c. the dies.
ce is a loose counter sunk washer to keep the dies one height and the pitch of
thread right.
ee is the cover plate to hold die block in place.
dd holds the worm-wheel with die block combined in their proper place.
"
is the adjusting set screw and nut to regulate spindle "mm.
K is a loose internal collar in front of y
enable
the latter being a gland screw to
*"*"the spindle for operator to be brought in a central position.
The dies to suit revolve indapendently to stocks moved by a worm wheel or
helical wheel the dies close in by a incline or conical hole which may be applied to
any rotary motion prefer these for adgusting my taps after having cavaties cut in
the taps the dies close by a screw in gland nut and adgusted by countersunk washer
fastened by two setscrews.
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, viz. —
Taps with cavities, cut at intervals across the threads not "
grooves or flutes"
and that my taps are not filed off at back of cutting edges but left cylindrical,
thereby preventing "gripping" &c. too greedy I claim further to drill holes down
the centre of my taps, and meet these by other boles drilled from bottom of cavities
(to centre hole). By these means the taps are enabled to become self lubricative
and considerably increased in strength.
My taps not being filed off as aforesaid, causes heat by friction enabling them to
perform their work much easier, besides cutting both ways.
66
"
The dies to suit revolve independently to stocks moved by a
worm wheel' 01'
"helical wheel." The dies close in by an inclined or conical hole, which may be
applied to any rotary motion, I claim these dies, for adjusting my taps after having
cavities cut in the taps. The dies close by a screw in gland nut and adjusted by
countersunk washer fastened by two set screws.
10th August 1891.
JOHN BARTHOLOMEW MCMULLEN.