Improvements in Dental Drills.
Year: 1895

page_text: Date of Application, 7th Sept., 1895
Complete Specification Left, 6th June, 1896-Accepted, 11th July, 1896
PROVISIONAL SPECIFICATION.
Improvements in Dental Drills.
We, LAWRENCE READ, Chairman of The Dental Manufacturing Co. Ld., of
6 to 10 Lexington Street, in the County of Middlesex, and WILLIAM ROBERTSON,
Foreman to the said Company, do hereby declare the nature of this invention to be
as follows:
The old and well known dental burr consists of a stem carrying a spherical head
having on it a number of inclined cutting edges radiating from the point
diametrically opposite to the stem. Such burrs are used for enlarging or clearing
out holes but they will not drill, that is to say cylindrical holes of any considerable
depth cannot be formed by continuously rotating them for they rapidly clog.
:
These burrs have however before been modified so as to form drills this has
been done by having only a single catting edge passing completely across the
head the other cutting edges all stopping short of the central point so that a
groove is left on each side of the central cutting edge.
According to this invention the burr is modified in another way for the same
purpose. All the cutting edges meet in a point or approximately so as before but
this point instead of being diametrically opposite to the stein is to one side. The
result of this is that when the drill is rotated cach cutting edge in succession
sweeps over the axial line of the hole. The inclination also of the cutting edges to
the stem is greatly increased which assist in clearing the hole.
Dated this 6th day of September 1895.
LAWRENCE READ.
W. ROBERTSON.
Improvements in Dental Drills.
We, LAWRENCE READ, Chairman of The Dental Manufacturing Co. Ld., of
6 to 10 Lexington Street, in the County of Middlesex, and WILLIAM ROBERTSON,
Foreman to the said Company, 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 :-
The old and well known dental burr consists of a stem carrying a spherical head
having on it a number of inclined cutting edges radiating from the point
diametrically opposite to the stem. Such burrs are used for enlarging or clearing
out holes but they will not drill, that is to say cylindrical holes of any considerable
depth cannot be formed by continuously rotating them for they rapidly clog.
These burrs have however before been modified so as to forin drills: this has
been done by having only a single cutting edge passing completely across the
head the other cutting edges all stopping short of the central point so that a
groove is left on each side of the central cutting edge.
According to this invention the burr is modified in another way for the same
purpose.
All the cutting edges meet in a point or approximately so as before but this
point instead of being diametrically opposite to the stem is to one side. The

page_text: inclination also of the cutting edges to the stem is greatly increased which assist
in clearing the hole.
DESCRIPTION OF THE DRAWINGS.
Figure 1 is a side elevation and Figure 2 an end view both to a greatly
magnified scale of a drill constructed according to this invention.
Figure 3 is a developed side elevation of one of the ridges, and Figure 4 is a
central section of the same.
a, are the cutting edges of the ridges, bare the leading faces which are
approximately radial and care the following faces which make an angle of
about 45° with the leading faces.
Having now particularly described and ascertained the nature of our said inven-
tion and in what manner the same is to be performed we declare that what we
claim is :-
1. A dental drill with a spherical head having upon it cutting edges which meet
or approximately meet each other but not at the point diametrically opposite the
stem.
2. A dental drill substantially as described and shown in the drawings.
LAWRENCE READ.
WILLIAM ROBERTSON.