Improvements in Twist and other Drills.
Year: 1893

page_text: Date of Application, 7th Dec., 1893
Complete Specification Left, 7th Sept., 1894-Accepted, 13th Oct., 1894
PROVISIONAL SPECIFICATION.
Improvements in Twist and other Drills.
FAIRBANK BREARLEY Engineer Baildon Green near Shipley Yorks JOSEPH
OVEREND Engineer 25 Lower Green Baildon Green near Shipley Yorks do
hereby declare the nature of this invention to be as follows:-
Our improvement relates to a certain new and useful improvement in twist and
other drills.
:
It effects the grinding of the cutting edges or lips of twist or other kinds of
drills for boring metals or other materials. It consists of a series of grinding lines
at suitable distances from each other, at suitable angles for various kinds of cutting
edges, to the axis, or the present "centre grinding line" of the twist or other
drills, parallel to which grinding lines the lips of the drill are ground, thereby
securing a more perfect drill point and consequently a more perfect hole.
Dated this 6th day of December 1893.
FAIRBANK BREARLEY.
JOSEPH OVEREND.
Improvements in Twist and other Drills.
We, FAIRBANK BREARLEY and JOSEPH OVEREND, both of Baildon Green
near Shipley Yorkshire, Engineers, 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, that is to say:
:--
It relates to a certain new and useful improvement in twist and other drills for
boring metal or other substances, whereby the cutting edges at the outer ends of
these drills may more readily be formed at the proper angle to the longitudinal
axes thereof and of the desired shape than they have been heretofore.
In order that our said invention may be readily understood we have hereunto
appended a sheet of drawings illustrative thereof, in which ;-
Figs. 1 and 2 are side and sectional views of a twist drill.
Figs. 3 and 4 are similar views to Figs. 1 and 2 respectively but are illustrative
of a straight drill.
Within the groove or furrow a of the drill bor b¹ we make lines or marks c for
the guidance of the user when sharpening or grinding the outer end of said drill.
These lines c are made at the proper or desired angle to the axis (shown by
broken liues A B) of the drill bor and are made in a series with appropriate
intervening spaces between them so that they will be distributed over the whole or
any part of the length of the grooves a in order that as the drill becomes shorter,
by being ground or sharpened in the well known manner, at all parts or any part
of it will be found one or other of these grinding lines in accordance with or
parallel to which the user has to grind the cutting edge d, thus the expensive
machinery and tedious devices at present employed as being necessary for effecting
the grinding of these edges at the proper angle to the axis are entirely dispensed
with, while cutting edges on the drills are produced which enable said drills to
bore holes perfectly cylindrical and straight.

page_text: Having now particularly described and ascertained the nature of our said
invention, and in what manner the same is to be performed, we declare that what
we claim is;-
1. In the production of twist and other drills the formation of a series of
guiding lines at an angle to the axes of said drills substantially as and for the 5
purposes specified.
Dated this 6th day of September 1894.
FAIRBANK BREARLEY,
JOSEPH OVEREND,
Per Samuel Hey,
Agent.