IMPROVEMENTS IN BORING BITS
Year: 1860

page_text: PROVISIONAL SPECIFICATION left by William Clark at the Office of
the Commissioners of Patents, with his Petition, on the 26th April
1860. A communication from abroad by Messrs. Gabriel Coulouvrat
and Auguste Genon, of Paris, in the Empire of France.
. I, WILLIAM CLARK, of 58, Chancery Lane, in the County of Middlesex,
Engineer & Patent Agent, do hereby declare the nature of the said Invention
for "IMPROVEMENTS IN BORING BITS," to be as follows:-
The new boring bit which is the subject of this Invention is intended to
pierce wood and stone, and will do so with much more facility than other
tools for this purpose, and works with greater perfection. The hole can be
bored of any size, that is to say, that what cannot be done by one bit can be
done by several bits in succession. The English centre bit being of one piece,
if the point or cutting edge breaks it is of no further use. The tool which I
wish to protect being of several pieces does not entail this inconvenience. If
either of the parts become deteriorated it is easy to replace it, and the whole
instrument is as good as ever, or nearly so. This centre bit can be put in
motion by a brace with a key lever, or double-armed lever, which may be
substituted with.advantage for that purpose. Its form permits of the detached
fragments of wood or stone finding their way out without being obliged to take
out the bit to clear it.

page_text: of cast iron, and with hollow spaces to render it light. The stem m is forked,
and enters the body by the holes n, n, and is fixed by the screws o, o.. Fig. 2
shows a plan and section through the screws; p, central pivot fixed to the
body c by a screw V; D, cutter, it is fixed by a screw d; this screw can slide
in a lengthened hole e, so as to raise and lower the cutter D according to the
use and requirements of work; f, sloping surface in the body of the tool to
permit of the passage of the fragments, and called the spout; d', diamond-
pointed cutter, it is held by a screw 9. This cutter has a slot or opening, so
as to regulate it, as in cutter D. Fig. 3 is an elevation, showing the lengthened
hole in which works the screw of the cutter D, and mode of attaching the
body to the stem m, as above described. Fig. 4 is a plan, showing cutter D',
cutter D, and holes n, n, to receive the fork of the stem m. Fig. 5 shows
another bit of larger size; this bit has no centre pivot, it is replaced by a tube gat
the bottom of c; this tube enters the hole made by a previous bit, and performs
the office of the pivot, thus this boring bit cannot be used without previously
making a hole equal in diameter to q. The bit, Fig. 5, having finished its
work, another bit of larger size, but with the part 9 of the diameter equal to
the preceding bit used, and so on, thus constituting a series, which are used
when it is necessary to obtain a hole of large diameter; f, slope for discharging
fragments; d', diamond-pointed cutter; m, stem adjusted to the body, & either
round or square, fixed with key or screw. Fig. 6 is a horizontal plan of
Fig. 5. The base of the body can be of different forms, it can be .concave or
convex, & of an entire or truncated cone, or of other forms.