FIELD OF INVENTION
The present invention relates to an improved parting tool holder adapted on a
CNC Cut off machine. More particularly, the invention relates to an improved
parting tool holder which can resist very frequent damage of the parting tool,
blade holding the tool and even the tool holder.
BACKGROUND OF THE INVENTION
In any machining operation, the tool is the weakest link. It is so designed that in
case of any eventuality, the tool should break and the Machine tool and Job to
be protected. Having stated so the tool has to perform well given the
recommended cutting parameters for the cutting tool and the mechanical
properties of the job material to be machined. The total quality and productivity
of the job depends on the type of tooling used, rigidity of the machine tool, the
machining parameters and the job clamping. For machining, carbide inserts are
used. All the carbide inserts used have got a life (Time per cutting edge or
meters of cutting per cutting edge). For parting off tubes in the CNC modern cut,
the tooling consist of a parting carbide insert mounted on a blade and is fixed to
a tool holder which is mounted on the machine tool slide. Each tool manufacturer
has its own design of parting tool holders but basically consisting of a carbide
insert, blade and tool holder. All tool manufacturers were approached for tooling
for parting of tubes giving the tube diameter, tube thickness, tube material and
the machine tool specification. Trials were conducted with different tool
manufacturers for a given tube diameter, thickness and material. Most of the
cases the parting insert was getting damaged, a few the blade was damaged
given the recommended cutting parameters as per the supplier. In one case the
insert and blade was very good but the tool holder failed.

OBJECTS OF THE INVENTION
It is therefore an object of the invention to provide an improved parting tool
holder on a CNC Cut off machine which is capable of resisting very frequent
damage of the Parting tool, blade holding the tool and even the tool holder
withstanding all the cutting forces for parting of tubes.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
Fig.l - Shows the existing two side support parting tool holder
Fig.2 - Shows the three side support parting tool holder according to the
invention.
DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT OF THE
INVENTION
According to the invention there is provided in the tool holder a groove which
has three butting surfaces with the blade. The blade is clamped with three
screws in this groove in the tool holder thereby restricting all degrees of freedom
of the blade in the holder. The top butting surface of the blade with the tool
holder is the new addition in this design of the holder to withstand shock load
thereby eliminating the chance of breakage of the tool holder, insert and the
blade.
Figure 1 Shows the existing two side support parting tool holder.
The tool holder (1) has a square shank to suit the GNC modern cut off machine
slide. There is a groove in the holder which houses the blade (2) which is
clamped to the holder with three screws (4). The carbide insert (3) is fixed to the

blade (2) by a self locking mechanism. In this holder the blade is supported only
on two sides and has to withstand all the cutting forces while parting.
Figure 2 Shows the unique design of the three side support parting tool holder.
The tool holder (1) has a square shank to suit the CNC modern cut off machine
slide. There is a groove in the holder which houses the blade (2) which is
clamped to the holder with three screws (4). The carbide insert (3) is fixed to the
blade (2) by a self locking mechanism. In this holder the blade is supported on
three sides to withstand all the cutting forces while parting. Trials were
conducted with this holder for all tube diameters, all tube thickness, all material
specifications and with a wide range of cutting parameters and the holder
preformed very well.
This tool holder can be adapted in any conventional modern cut off or parting
machines.
The groove made on the top face of the holder (1) that houses the blade (2) is
milled suiting the width of the blade so that the two sides of the blade just rest
on the wall of the groove so that there is no room for the blade to move when
subjected to cutting forces. The depth of the groove or slot is made equal to the
height of the blade. The first support on the angular side of the holder is milled
so that angular side of the blade rest on the wall without having any room for
movement. At this condition three screws are tightened to fix the blade tightly on
the holder. By fixing the blade in this manner on the tool holder with three
support, the problem of frequent breakage of insert, blade or even the tool
holder is totally avoided.
WE CLAIM
1. An improved parting tool holder adapted on a CNC Cut off machine
comprising;
a square shank tool holder (1) suiting the slide of the CNC Cut off
machine;
a groove made on the face of the tool holder (1);
characterized in that,
the groove milled on the tool holder (1) has three wall supports when the
side of the blade rests on these three wall supports leaving no room for
the blade (2) to move while the blade (2) is fixed on the tool holder (1) by
three screws (4).
2. An improved parting tool holder as claimed in claim 1, wherein the depth
of the groove is milled equal to the height of the blade (2).

An improved parting tool holder adapted on a CNC Cut off machine consists of a
square shank tool holder suiting the slide of the CNC Cut off machine. A groove
is made on the face of the tool holder which is milled to suit the blade of the
holder that carries the parting carbide insert. The blade is supported by three
wall supports of the groove. The depth of the groove is made equal to the height
of the blade. The blade is fixed on the face of the holder and in the groove by
three screws.