Improvements in or relating to Deep Boring Tools.
Year: 1899

page_text: Date of Application, 21st July, 1899 -Accepted, 30th Sept., 1899
COMPLETE SPECIFICATION.
Improvements in or relating to Deep Boring Tools.
I, WILLIAM HENRY MACGARVEY, Wholesale Manufacturer, of Galizia, Austria,
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:-
This invention relates to improvements in eccentric boring tools.
The object of the present invention is to provide a bit or drill having a step
at the end of the eccentric side of its edge, so that the user of the bit
or drill is enabled to simultaneously bore holes and enlarge the same, for
instance, to a larger diameter than that of the tubing to be afterwards inserted.
Eccentric boring drills or bits are used, as is well known, for the purpose of
boring a hole of a larger diameter than that of the tubing to be afterwards inserted
therein.
Experience has proved that in order to attain the above purpose in a perfect
manner and to render the boring easy in any kind of rock or material, the edge
of the drill or bit must have a step or step shaped recess, instead of presenting a
straight line or edge like the boring tools known and used until now. However
such step need not be provided on either side of the front boring edge, as has
been proposed, but must be provided at the end of the eccentric portion of the
tool only, which step then serves as the enlarging edge.
This new boring tool or bit is represented in the accompanying drawings, in
which
Figure 1 shows the same in side view partly in section within the tubing,
Figure 2 shows it at work, and
Figure 3 is a side elevation also partly in section.
As may be seen from the drawings, an edge b is provided in addition to the
principal or boring edge a so as to form a step with the latter, whereby when the
tool is at work the edge a serves to bore in advance, while the edge b, provided
at one side of a, enlarges the hole, thus a hole may be easily sunk in any kind
of rock, the diameter of such hole exceeding that of the tubing by, say, about
two inches.
This improved drill or bit above described may be applied both for dry boring
and for boring combined with rinsing with water; in the latter case the bit must
have an axial bore in its body (Figure 2).
I am aware that drills or bits have been used having on one side at a considerable
distance above the front-boring edge an eccentric projection for reboring the hole,
which drills or bits, however, present the inconvenience that when meeting brittle
material they cease to cut regularly or may even be caused to deviate from the
normal direction. Hence it follows that the action of such tools is essentially
lifferent from that of my improved drill or bit, the enlarging edge of which works
mmediately upon the same material as the front-boring edge.

page_text: Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, I declare that what
I claim is:-
1. An eccentric enlarging boring tool, the main or front-boring edge of which
is provided at the end of its eccentric side and but slightly above the same
with a step to form a one sided second or enlarging edge, substantially as
described.
2. An eccentric enlarging boring tool substantially as described and illustrated
in Figure 1 or in Figure 2 of the accompanying drawings.
גד
1 ..
BOULT & WADE,
Agents for the Applicant.