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WORK HOLDING DEVICES IN
LATHE
By N.PRADEEP RAJ
(12LM17)
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Four jaw chuck or independent chuck
Three jaw chuck or self-centering chuck
Air or hydraulic operated chuck Magnetic chuck
Collet chuck
Combination chuck
Drill chuck
TYPES OF CHUCKS
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As the name indicates this chuck has four jaws for holdingthe work each jaw is independent to move.
Advantages
Any type of work piece can be held easily
High grip is possible as four jaws are employed
Disadvantages
Centering is a little difficult process
Semi skilled labor are required
FOUR JAWS OR INDEPENDENT CHUCK
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THREE JAW CHUCK OR SELF CENTERING
In Three jaws for holding the work piece, and if one jaw ismoved then all the other jaws also move by same distance.
This mechanism is obtained by engaging pinions which
meshes with the teeth cut on the under surface of thechuck. This chuck is also called UNIVERSAL CHUCK
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ADVANTAGES
Centering process is not necessary as all the jaws moves
at a time
Consumes less time for mounting and un mounting the
work piece.
DISADVANTAGES
Grip is not so high as only three jobs are employed
All type of jobs cannot be mounted on these chucks, as
they are useful in machining only axis symmetrical objects
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As the name indicates it is a combination of both three-jaw
chuck and four-jaw chuck. It acts as both self-centering and
independent chuck. This is obtained by engaging a scroll disc
at the backside of jaws.
COMBINATION CHUCK
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MAGNETIC CHUCK
In this chuck magnetic force is used for holding
the work piece.
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ADVANTAGES
Work pieces in which damage due to the jaws of chucks is
not tolerated can be effectively machined by using this chuck
If the work to be held is of very small size and cannot be
hold by the above three chucks then this chuck can be used
DISADVANTAGES
All type of jobs cannot be held
Size of the job affects the efficiency of the holding
All type of materials cannot be held as it works on
magnetic property only magnetic materials can be held.
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This is also called as pneumatic chuck as it is beingoperated by hydraulic or air energy. This chuck holds the work
piece due to the pressure generated in the cylinder.
AIR OR HYDRALIC OPERATED CHUCK
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This type of chuck is used when the work to be held is very
long in size.
COLLET CHUCK
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COLLET CHUCK
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This chuck is used for holding the tool in the drillingmachines. This also plays a role in holding taper shanks
on a lathe for easy machining of the job on which holes
are to be drilled.
Drill chuck
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Rest is a work holding device, which is used to hold the
work piece when the work piece of very long length areto be held. In general when a long piece is to be held it
may have directly held then there arises deflection in the
work piece due its own weight. So to prevent the
deflection in the work piece rests of various types areused. Some of the rests being used are
Rests
1) Steady rest
2) Follower rest
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