IMPROVEMENTS IN DRILLS AND IN MACHINERY FOR MAKING THE SAME
Year: 1871

page_text: PROVISIONAL SPECIFICATION left by Thomas Palmer Baker at the
Office of the Commissioners of Patents, with his Petition, on the
5th May 1871.-A communication from abroad by Henry Purdon
Bell, of Folly Lake, in the County of Colchester, Nova Scotia, in
the Dominion of Canada, and Frederic Newton Gisborne, of West
Strand, in the County of Middlesex, but at present residing in
Halifax, also in Nova Scotia, in the Dominion of Canada.
I, THOMAS PALMER BAKER, of West Strand, in the County of Mid-
lesex, of the Royal Navy, and Companion of the Bath, do hereby
leclare the nature of the said Invention for "IMPROVEMENTS IN DRILLS
AND IN MACHINERY FOR MAKING THE SAME," a communication to me from
abroad by Henry Purdon Bell, of Folly Lake, in the County of
Colchester, Nova Scotia, in the Dominion of Canada, and Frederic
Newton Gisborne, of West Strand, in the County of Middlesex, but at

page_text: present residing in Halifax, also in Nova Scotia, in the Dominion of
Canada, to be as follows:-
The object of this Invention is to effect the boring of rock in mining
or quarrying by making a drill which when struck with a hammer or
let fall by gravitation or propelled from a machine actuated by any
convenient power cuts its way by the combined simultaneous action of
concussion and self-acting rotation.
The improvements consist of three parts namely the drill point, a
swedge, and one or more sockets or guides, in which to rest the drill
bar during the formation of the drill point.
The drill point is made of a twisted form with its edge 'straight in
the length or width of the point and not bevilled like other rock drills,
by which means the drill has a self-acting power of rotation while
operated. By giving to these drill points.a_twisted form the metal is
withdrawn from the centre of the point where it is not wanted and
disposed in the outer edges or ears which are the first points to drill in
-all ordinary drills.
It is intended by the Inventors that these drill points should be
proportioned with reference to the hardness and texture of the rock to
be operated upon, the degree of twist increasing with the hardness of
the rock and vice versa. These twist point drills may be formed by a
handy blacksmith without any swedge or extra tools whatever, the
application of the swedge is either to enable mechanics or labourers to
form these drill points without difficulty on a first trial or to facilitate
the twisting of the point.
Swedges for making these twist drill points are formed of a block of
mallcable iron faced with cast steel in which the mould of the drill
points to be made is formed by driving therein while such block is hot a
drill point of the form intended to be used. The lips of the mould so
impressed are then cut away for about one-fourth of its depth to allow
the blunt end of a heated steel bar to enter to that depth.
The method of forming these drill points by swedge is as follows :-
The drill bar upon which it is sought to form a point is heated at the
end, laid while hot in one or more sockets or guides with its heated end
resting in the lips of the swedge, the drill bar is then driven home in
the swedge by pressure applied on the back end of the bar, and when

page_text: taken out a few blows with a hand hammer to give a neater edge
completes the operation of forming the point, the pressure applied in
swedging improves the texture of the steel. The sockets or guides arc
formed open at the top and to fit the steel bar, a key passing through
holes being employed to hold the steel bar in such guides.