Hello friends, Today we are going to tell you about work
holding devices in lathe machine.
Basically, work holding devices in lathe machine are the lathe machine accessories and function of this holding device we will discuss further in detail.
The means of holding and supporting work or tool on a
lathe machine are called lathe machine accessories which are performed various
operations in a lathe machine.
But nowadays CNC type lathe is most widely used in the industry because this type of lathe is fully automatic.
So without wasting any time let’s know work holding devices in lathe machine.
Work Holding Devices in Lathe Machine
Chuck, Face Plate, Lathe Centers, Steady Rest and Mandrels, etc.
are common lathe machine accessories and the functions of these holding tools work as work holding devices.
There is the following work holding devices in the lathe machine:
- Chuck
- Centers
- Steady Rest
- Carriers
- Driving Plate
- Face Plate
- Mandrel
Lathe Chuck
Chuck is one of the types of work holding devices in lathe machines that are used in various operations for holding the workpieces or a job.
Types of Lathe Chuck
There are following types of chuck are used:
- Four Jaw Chuck
- Three Jaw Chuck
- Magnetic Chuck
- Collet Chuck
- Combination Chuck
- Air Chuck or Hydraulically Operated Chuck
- Drill Chuck
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| Types of Lathe Chuck |
Four Jaw Chuck
It is also called Independent Jaw Chuck which consists of
four jaws and each jaw can be moved separately by chuck 'key'.
These jaws are reversible and have steps made on them, which
can be used to mount workpieces or a job
of different sizes.
This chuck is used to hold regular and irregular shaped jobs, heavy components, and large diameter jobs.
Advantages of Four Jaw Chuck
- The job can be true to a precision of 0.02 mm.
- The workpieces can be set for eccentric turning.
- Larger diameter jobs can be easily held using reversible jobs.
- Irregular shaped jobs can be easily held.
- It has more gripping power.
Disadvantages of Four Jaw Chuck
- The workpieces setting is more difficult than the three jaw chuck.
- It is not suitable for mass production.
Three Jaw Chuck
It is also known as a Universal Chuck, Self-Centric Chuck, and Concentric Chuck which consists of three jaws that work at the same time,
with this type of chuck having separate internal and external jaws are
found.
In a three-jaw chuck should hold a round job and the
hexagonal workpieces.
Advantages of Three Jaw Chuck
- In three jaw chuck, cylindrical and hexagonal workpieces can be easily set in the center.
- It is suitable for mass production.
- Setting up jobs is easy.
Magnetic Chuck
The job on this chuck is hold by magnetic power.
Magnetic chuck is suitable for mass production of thin
sectioned jobs and components.
The following types of Magnetic Chuck are found
- Permanent Magnetic Chuck
- Electromagnetic Chuck
Collet Chuck
Collet chucks are mostly used to hold the jobs less than 25
mm in diameter.
Collets are found in sizes up to 25 mm in diameter.
Collet chuck is more perfect, saves time in tying the work, and increases the speed of production.
Combination Chuck
Generally, it is a four-jaw chuck in which the jaws can be
adjusted either independently as the four-jaw or together with the three-jaw
chuck.
This type of chuck is used in places where duplicate
workpieces are available.
A self-centering socket is used in the body of the chuck to
tighten the workpieces.
Air Chuck or Hydraulically Operated Chuck
It is used for mass production work as it has a quick and
effective gripping capability.
Its mechanism consists of a hydraulic or air cylinder
mounted on the back end of the headstock and rotating along with it.
Fluid pressure is transmitted to the cylinder by operating
the valves.
It is either manual or automatic.
The movement of the piston transmits to the jaws and links
of the connecting rods, allowing the workpieces to be gripped properly.
Drill Chuck
A drill chuck is a tool holding device used to hold drill bits tool or drill in a drilling machine.
Lathe Centers
The Center is a work holding devices in a lathe that is used to support long jobs in between
headstock and tailstock to carry out a lathe operation.
Lathe centers are often made of high carbon steel and then it is hardened, tempered, and grinded.
The center which rotates with a job in the nose of the
headstock spindle is called a live center.
The center which is set up at the tailstock is stable and hence it is called the dead center.
Both centers are
identical in texture.
Lubricants for dead centers should be used, and lubricants are
not required for the live center.
The top angle of the corner point of the lathe center is 60
° and the body has a morse taper shank and a tang.
Different Types of Lathe Centers
There are the following types of lathe centers:
- Ordinary Center
- Half Center
- Tipped Center
- Ball Center
- Pipe Center
- Revolving Center
- Inserted Type Center
- Self Driving Live Center
- Female Center
- Swivel 'V' Center
See in a figure different types of lathe centers, which are described below in detail.
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| Types of Lathe Centre |
Ordinary Center
It is a common type of center that is used for simple tasks.
Half Center
The tip portion of this center is relieved by less than
half.
It is used when facing the job without disturbing the
setting.
Tipped Center
It is a wear resistant center in which the tip of carbide or hard alloy is brazed in the nose of a simple steel shank.
Ball Center
At the tip of this center, a ball is formed which reduces
wear and tear.
It is particularly suitable for performing taper turning by the offset method.
Pipe Center
Its tip is flat and It is used to support pipes,
shells, and hollow-end workpieces.
Revolving Center
It is a non-friction center, also known as a revolving dead center.
It is used where large and heavy jobs have to be run at high
speed.
Inserted Type Center
It is a saving center
as only a small high speed insert is replaced.
Self Driving Live Center
This center has points cut around the periphery of the center
to give good griping to the job and to get the drive.
It is mounted on the headstock spindle.
It is used when machining the entire length of a job in one
setting.
It cannot be used on hard jobs but only on soft jobs.
Female Center
This center is used to support that types of jobs on which it is not
possible to make a countersink hole.
Swivel 'V' Center
Using this center to support the job in its 'V' part and using drill or drill bits in the headstock spindle to drill holes across the job.
Steady Rest
Steady rest is a type of work holding devices in lathe machine
that is used to hold or support long cylinders or thin jobs.
The job is supported by this to maintain a stable position
of the job while turning.
Types of Steady Rest
Often the following types of steady rests are used:
- Traveling Steady Rest
- Fixed Steady Rest
- Revolving Steady Rest
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| Types of Steady Rest |
Traveling Steady Rest
It is also called follower steady rest which is joined with a cross slide on the opposite side of the cutting tool.
It has two adjustable jaw pieces and runs with a carriage on the bed.
Fixed Steady Rest
Fixed steady rest can be fixed in any fixed position on the
bed of the lathe.
It has three adjustable jaw pieces which are controlled by different screws.
Revolving Steady Rest
Revolving steady rest is like a fixed steady rest with the lower part fixed on the bed of the
lathe.
It is also used to hold square and hexagonal rods.
Lathe Carriers
The carrier or dog is a work holding devices in lathe
machine used to hold a job when it needs to be fixed between the centers.
Work or a job inserted into the hole of a carrier and then tightly
fixed.
Types of Lathe Carriers
Often the following types of lathe carriers are used:
- Straight Tail Carrier
- Bent Tail Carrier
- Adjustable Carrier
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| Types of Lathe Carrier |
Straight Tail Carrier
The tail of this carrier is straightened which is set
against the driving pin of the catch plate, it provides a positive drive to the
job.
Bent Tail Carrier
The tail of this carrier is bent which is attached in the
'U' slot of the catch plate to drive the job.
Adjustable Carrier
It is a clamp type carrier that consists of a clamping
plate and an adjustable screw.
It is used to hold small diameter jobs and square and
rectangular shaped rods.
Driving Plate
It is a circular plate
used when turning jobs in between centers.
It is used with a straight tail or bent tail carrier to give
a positive drive to the job.
Types of Driving Plate
There are following types of driving plates are used:
- Catch Plate
- Driving Plate with Pin
- Safety Driving Plate
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| Types of Driving Plate |
Catch Plate
This plate consists of a 'U' slot and an elliptical slot in
which the bent tail of the lathe carrier is attached.
This requires a shorter length for clamping.
Driving Plate with Pin
This plate consists of an ejected pin that locates the
straight tail of the lathe carrier.
It provides a positive drive to the workpieces.
Safety Driving Plate
It is made of cast iron which is similar in shape to a
driving plate but has a cover that protects the operator from injury.
There is also a stepped collar on the back of this driving
plate.
Face Plate
This is a circular plate used to perform various turning
operations on a large flat, irregular shaped jobs, castings, etc.
The face plate is fixed on the lathe spindle and the job can
be mounted on it to perform turning operations.
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| Face Plate |
Lathe Mandrel
The lathe mandrel is used to hold the workpieces or a job
that is already bored or drilled.
The mandrel is often
hardened with tool steel and grinded to a specified size.
It is grinded on a 1: 2000 taper.
Types of Lathe Mandrel
The following types of the mandrel are often used:
- Plain Mandrel
- Stepped mandrel
- Collar Mandrel
- Screwed Mandrel
- Cone Mandrel
- Gang Mandrel
- Expansion Mandrel
- Taper Shank Mandrel
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| Types of Mandrel |
Plain Mandrel
This mandrel is more common with a slight taper (1: 2000)
that allows the workpieces to griping helps in the right way.
It is suitable only for one size bore.
Stepped mandrel
This mandrel has steps with different diameters.
Different diameters of workpieces can be fitted on this
mandrel.
Collar Mandrel
Collars are made on this mandrel, which reduces the weight
of the mandrel considerably.
It is used for turning large diameter workpieces.
Screwed Mandrel
Threads are made at one end of this mandrel and a collar is
formed on it.
It is used to mount workpieces that have internal
threads.
Cone Mandrel
This mandrel is used to hold workpieces of different
diameters of the hole.
This mandrel has a solid cone on one side and a sliding cone
and nut on the other side which consists of threads.
The workpieces are held onto two cones, and the sliding cone
is adjusted and the nut is tightened to hold the workpieces in the correct
position.
Gang Mandrel
This mandrel has a parallel body with a fixed collar at one
end and a spacing collar at the other end.
Its ends are made of
threads with a washer and a nut attached to it.
Several identical workpieces can be mounted between fix and
spacing collars on this mandrel and clamp the nut tightly.
Expansion Mandrel
This mandrel has a solid mandrel and a slanted sleeve.
This type of mandrel is more useful for workpieces whose diameters
are different from the standard size.
This type of mandrel is also more useful for repairing
workshops.
Taper Shank Mandrel
The taper shank of this mandrel is made to fit in the
headstock spindle.
So, Here I discussed work holding devices in lathe machine
which are the lathe machine accessories, and the function of these holding tools also
known in detail.
I hope you all enjoy this topic if any queries you can contact me through email or the contact us page.
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Thank You.
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