FIELD OF THE INVENTION
The present invention generally relates to a method of Turning/8oring on
horizontai machining conters. More particular \yt the present invention relates to a
Boring Bar having a fine tool adjustment means adaptable to horizontal
machmrng centers.
BACKGROUND OF THE INVENTION
At present, tuming/boing process on horizontal machining centers is carried out
by using boring bars with cutting tool clamped in Its slot by a screw as shown in
figure 3(a) and 3(b). For machinhg for example, configurating an exact diameter
on components, the tool in undamped by unscrewing the screw and then set
manually by a trial and error method. After a cut is taken on the component, the
diameter of the component is measured and the tool is reset again. To achieve a
fine toleance it takes a substantially higher time to set the tool. Thus the
processing time gets unusually extended leading to high cost.
OBJECTS OF THE INVENTION
An object of the present invention is to propose a boring bar having a fine tool
adjustment means whitch eliminates the disadvantage of the prior art.
Another object of the present invention is to propose a boring bar having a fine
tool adjustment means, which achieves a tolerance in steps of 0,01 mm.

3
Yet another object of the present invention is to propose a boring bar having ft
fine tool adjustment means which ensures quick and accurate setting of the tool
leading to reduction in tool setting time.
A further object of the present invention is to propose a bortng bar having a fine
tool adjustment means which eliminates the step of manual setting of the tool
for fine tolerance machining.
SUMMARY OF THE INVENTION
Accordingly, there is provided a boring bar adaptable to horizontal machining
centers having a fine adjustment means comprising: a main bar having a shank
corresponding to machine spindle mounting device, a tool slot for t tool and
atieast two holes for clamping the tool via a square head bolt; a (ever fixabte on
the main bar via a first hole by means of a hexagonal head bolt, a micrometer
head screw fixable to the main bar via a second hole through second hole of
lever with a spherical washer on the lever under the screw, and atteast two
springs freed on the holes of the lever and the main bar.
The micrometer head rotation provides for fine movement of the tool in steps of
0.01 mm and the spring aids in back movement of the tool,
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
Figure l(a) - shows a boring bar having a fine adjustment means according to
the present invention.

4
Figure 1(b) - shows the boring bar having a fine adjustment means with a
micrometer head screw according to an embodiment of the
present invention.
Figure 2 - shows the layout of a main bar, a lever, a spring, a hexagonal head
screw, a spherical washes a plurality of screws, and a hexagonal
head bolt ami washer.
Figure 3(a) and (b) - show the diagram of prior art with tool ctamped in boring
bar with screws.
DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT OF
THE INVENTION
Figure l(a) shows a boring bar which comprises a main bar (1) fixed on the
machine spindle by its shank. A lever (2) fixed on the mam bar (1) by means of a
hexagonal head bolt (7) and a washer (8). A micrometer head screw (4) Js
screw ably disposed, in the main bar (1) with a spherical washer (5) on the fever
(2). Atteast two springs (3) i$ fixed in the holes of the lever (2) and the main bar
(1). Atleast two square head bolts (6) are provided for clamping the tool
Figure l(b) shows a boring bar with a micrometer head screw (4).
As shown in figure 2, the main bar (1) is fixed/mounted on the machine by the
shank (suiting to machine tool).

5
The lever (2) is placed on the main bar (1) through a guiding key of the main bar
(1).
A threaded hole (H1) is provided for clamping the lever (2) through a first hole
(h1) with the main bar (1) via a hexagonal head bolt (7) and a washer (8).
Before clamping the lever (2), atleast two springs (3) are inserted in a first pair
of holes (H3) of the main bar (1) and it goes jn a second pair of holes (h3) of the
lever (2) while clampurig.
The Spherical washer (5) is placed on the lever (2) and the micrometer head
screw (4) is Inserted In a second hole (h2) of the lever (2) and screwed in a third
hole (H2) of the main bar (1).
During machining, the tool is clamped in a tool slot S by the atleast two squane
- head boits (6) through a fourth hole (H4) and a fifth hole (h4) of the main bar
(1), and the lever (2) respectively.
While fmishing the process of boring/turining, the bolt (6) in foe fourth hole (H4)
of the main bar (1) is unscrewed and a finer adjustment of the tool is done bv
the micrometer head screw (4).
Accuracy of the tool movement is ensured by the atteast two springs (3) and the
guiding keys.

6
The bolt (6) remaining in the fourth hole (H4) of the main bar (1) after final
adjustment is tightened.
Each rotation of the micrometer screw (4) causes a movement of 0.01 mm to the
tool. The micrometer head divisions with actual movement of the tool is
calibrated when a complete rotation is given to the micrometer serew (4).

7
We Claim
1. A boring bar adaptable to horizontal machining centre, having a fine
adjustment means of the machine tool in steps of 0.01 mm, the boring
bar comprising:
- a main bar (1) having a shank adaptable to the horizontal
machining centre and a tool slot (s) for clamping of the tool
including a fourth hole (H4) for damping;
- a tever (2) fixable on the main bar (1) by a first hole (h1) of the
lever (2) on a threaded hole (H1) of the main bar (1) by means of
a hexagonal head bolt (7);
- a micrometer head screw (4) fixable on the main bar (1) with the
lever (2) for fine adjustment of the tool;
- atieast two square head bolt (6) fixable to the main bar (1) and the
lever (2) for clamping me tool, and
- atteast two springs (3) fitted in between a first pair of hole (H3) of
the main bar (1) and a second pair of hole (h3) of the lever for
accurate setting of the tool.

8
2. The boring bar as claimed in claim 1, wherein the lever (2), the at least
two springs (3), the micrometer head screw (4), a spherical washer (5),
the atleast two square head bolts (6), the hexagonal head bolt (7) and a
washer (8) together constitute a fixing, moving and setting means,
3. The boring bar as claimed in claim 1, wherein the micrometer head screw
(4) has corresponding number of divisions marked with a thread pitch
combination so that one division rotation of the screw (4) results in 0.01
mm movement of the tool.
4. The boring bar as claimed in any of the preceding claims wherein the
lever (2) is made of hardened spring steel.
5. The boring bar as claimed in any of the preceding claims wherein the
lever (2) has a line marking in a flat centre portion for reference to
rotation of micrometer head screw (4),
6. The boring bar as claimed in any of the preceding claims wherein the
main bar (1) is made of case hardened alloy steel.
7. A boring bar adaptable to horizontal machining centre, having a fine
adjustment means of the machine tool in steps of 0.01 mm as
substantially described herein with reference to the accompanying
drawings.