IMPROVEMENTS IN BORING TOOLS TO BE USED IN LATHES AND OTHER MACHINES
Year: 1885

page_text: I THOMAS BRAMWELL, of 36 Princess Street, Portwood, Stockport, in the
County of Chester, Engineer, do hereby declare the nature of said Invention for
IMPROVEMENTS IN BORING TOOLS TO BE USED IN LATHES AND OTHER MACHINES,
to be as follows:-
The object of my Invention is to make a boring bar to carry varying sizes of
cutters which cutters can be readily moved or expanded to compensate for wear or
for other purposes.
In performing my Invention I make a boss at one end of the boring bar through
which is cut a slot or slots for the cutters; in front of this slot the boss is reduced'
in diameter to form a projection which has a fine thread cut upon its outer surface
and it is drilled up some distance passing through the alot with a thread cut in the
hole; the cutters consist of pieces of steel fitted into the slot or slots, and these
pieces are bevelled where they meet in the centre.
•
To secure the cutters after putting them in their places a collar preferably some-
what smaller in diameter than the boss is screwed on to the projecting end of the
boss, a washer is placed between the cutters and collar, and a set screw with its
end coned to correspond with the bevelled cutters is screwed into the boss until its
coned end bears against the bevelled ends of the cutters so that by moving the
screw further the cutters can be expanded to the desired diameter. When this
is done the collar is tightened fast up to the washer and cutters and the set screw
is then locked by a nut or nuts against the end of the box when the tool is ready
for use.
To alter the diameter or compensate for wear the collar is slackened and the set
screw moved further into or from the cutters; when the parts are again secured
and the tool is ready for use.

page_text: "
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Improvements in Boring Tools to be Used in Lathes and
other Machines.
I THOMAS BRAMWELL, of 36. Princess Street, Portwood, Stockport, in the
County of Chester, Engineer, do hereby declare the nature of said Invention for
IMPROVEMENTS IN BORING TOOLS TO BE USED IN LATHES AND OTHER MACHINES,
and in what manner the same is to be performed, to be particularly described
and ascertained in and by the following statement :—
The object of my Invention is to make a boring bar to carry varying sizes of
cutters, which cutters can be readily moved or expanded to compensate for wear or
for other purposes.
In performing my Invention I make a boss at one end of the boring bar through
which is cut a slot or slots.for. the cutters, in front of this slot the boss is reduced
in diameter to form a projection which has a tine thread cut upon its outer surface
and it is drilled up some distance passing through the slot with a thread cut in the
hole;
the cutters consist of pieces of steel fitted into the slot or slots. and these
pieces are bevelled where they meet in the centre.
To secure the cutters after putting them in their places, a collar preferably some-
what smaller in diameter than the boss is screwed on to the projecting end of the
boss, a washer is placed between the cutters and collar and a set screw with its
end coned to correspond with the bevelled cutters is screwed into the boss until its
coned end bears against the bevelled ends of the cutters so that by moving the
screw further the cutters can be expanded to the desired diameter. When this is
done the collar is tightened fast up to the washer and cutters, and the set screw
is then locked by a nut or nuts against the end of the boss when the tool is ready
for use.
To alter the diameter or compensate for wear the collar is slackened and the set
screw moved further into or from the cutters when the parts are again secured
and the tool is ready for use.
And in order that my Invention may be fully understood and readily carried
into effect I will describe the accompanying sheet of Drawings reference being had
to the Figures and letters marked thereon. Figure 1. is an elevation, Fig. 2 a plan
and Fig. 8 a vertical section of a boring tool or bar made according to my invention;
Figs. 4. 5. 6. and 7 are detached views of parts of the same, and Fig. 8. is a sectional
view of an alternative construction of my improved boring tool.
a is the body or shank of the boring tool or bar which is shown flat, except near
the front end at a¹ where it is circular in section, the front end being reduced in
diameter and formed with an external and internal screw, thread. A slot is cut
through the enlarged portion a¹, into which are fitted two pieces of steel c which
form the cutters, the adjacent faces of these cutters are bevelled in opposite
directions as shown in Figs. 3 and 8, and their upper edges project above the the
upper surface of a¹. Over the cutters is placed a thin washer b, and a collar d
provided with a fine thread which screws on to the boring bar for the purpose of
securing the cutters in position.

page_text: A set screw with its point coned to correspond with the bevelled faces of the
cutters is screwed into the front of the bar, and locked when set or adjusted
by a nut e.
To increase the diameter of the cutting edges of the cutters, to compensate for
wear or for other purpose, the nut e and the collar d are slackened, so that the,
screw f may be turned in the direction necessary to force the cutters apart to the
desired distance, when this has been done the collar d and nut e are again screwed
up and the boring tool is ready for use.
Figure 8. represents a boring bar made according to my Invention but of a
slightly different form. In this construction the position of the set screw f is
altered, the lock nut e rests in a slot a³, formed in the bar a; the cutters c are
secured in position as before described by a screw collar d, the screw f being turned
to bear against and move the cutters outward.
When it is necessary to repair the cutters I prefer to remove the screw f and
screw a plug in its place into or on to the bar a, and then put the bar on the
centres of a lathe or grinding machine where the cutters can be turned or ground
in their working position.
It is evident that cutters of different sizes may be used in the same boring bar,
the shank of which may be either flat as shown or round or of any suitable section.
I have shown and described two cutters only, other numbers such as three might
be used.
:
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. The construction combination and arrangement of parts forming the improved
boring tool substantially as herein shown and described.
2. In a boring bar or tool the use of loose cutters with inner bevelled faces in
combination with a cone pointed screw for adjusting the same and means for
securing the cutters substantially as herein set forth.
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