1. safety regulations which should be
observed when operating a lathe.
p g
• Always wear approved glasses.
• Never attempt to run a lathe until you are familiar with its operation
operation.
• Never wear loose clothing, rings or watches when operating a lathe.
• Remove the chuck key before starting the spindle.
• Always stop the lathe before taking measurements of any kind.
• Always use a brush to remove chips.
• Before mounting or removing accessories, always shut of the power
supply to the motor.
• Do not take heavy cuts on long lender piece.
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• Do not lean on the machine. EN T
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2. TYPES OF LATHE
1. ENGINE 2 . MANUFACTURING 3 . PRODUCTION
LATHE
LATHE LATHE
1. BENCH LATHE
2. SPEED LATHE 1.
1 TURRET LATHE
3. TOOL ROOM / PRECISION LATHE 2. SINGLE SPLINDLE A.L
4.
4 GAP BED LATHE 3. NC LATHES
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3. TYPES OF LATHE
1. Engine l th
1 E i lathes,
2 Manufacturing lathes,
3. Production lathes.
1 . Engine Lathes :
(a) Bench lathe
(b) Speed lathe
(c) Precision lathe / Tool room lathe
(d) Gap bed lathe
BENCH LATHE :
# A small lathe mounted on bench
# Small in size
# Used for light machining on small work pieces. EN
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4. SPEED LATHE
# C b mounted on a bench or cabinet.
Can be t d b h bi t
# The fast setup , ease of operation, & low main-tenance.
# Used for light machining operations, turning, polishing, & finishing on
g g p , g, p g, g
small precision work.
TOOL ROOM LATHE
# Is equipped with special attachments and accessories to allow a variety
of precision operations to be performed.
# It is generally used to produce tools and gauges which are used in tool
and die work.
GAP BED LATHE
# The bed can be removed to increase the maximum work diameter
that can be revolved
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5. 2 . MANUFACTURING LATHE
# Are basically engine lathes which have been modified by the addition of
a tracer attach-ment or a digital readout system.
# Tracer lathes are used to duplicate parts which may be too difficult or
costly to produce on other types of lathes.
tl t d th t f l th
3 . PRODUCTION LATHES
# Are generally used when a large number of duplicate parts must be
produced.
TYPES OF PRODUCTION LATHES
(a) Turret lathes,
(b) Single-spindle automatic lathes,
(c) Numerically controlled lathes.
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6. TURRET LATHE
# Used to produce a large number of duplicate parts which may require
operations such as turning, drilling, boring, reaming, facing, & threading.
# On some turret lathes, as many as 20 different tools can be mounted
# Each tool may be rotated into position quickly and accurately.
# Once the tools have been set, each part is quickly and accurately
produced
SINGLE SPINDLE AUTOMATIC LATHE
# designed to automatically mass produce parts which require
mass-produce
primarily turning and facing operations.
# Automatic lathes generally have two tool slides mounted on the
carriage.
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# The front-slide tooling is used for turning and boring operations.
# The rear-slide tooling is used for facing, undercutting, chamfering,
and necking operations EN
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7. NUMERICALLY CONTROLLED LATHE
# One of the latest modifications of the basic engine lathe
lathe.
# This lathe, controlled by numerical tape, is used primarily for
turning operations and can economically and automatically
produce shafts of almost any shape
shape.
# This lathe can perform most types of lathes and provides
saving in tooling, setup, and cycle time
Size of the Engine Lathes
# The size of an engine lathe is determined by the maximum diameter of
work which may be revolved over the bed.
# The length of a lathe is stated by the length of the bed.
The size of a lathe is measured by :
1. Length of bed
2. Swing, the largest diameter that can be rotated EN
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3. Maximum useable distance between centers
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8. LATHE……………….
# A support for the lathe accessories or the work piece.
# A way of holding and revolving the work piece.
# A means of holding and moving the cutting tool.
MAIN PARTS OF ENGINE LATHE AND ACCESSORIES
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10. MAIN PARTS OF ENGINE LATHE
1. BED
2. HEADSTOCK
3. TAILSTOCK
4. CARRIAGE
1. BED
The bed is a heavy rugged
casting made to support the
working parts of lathe. BED
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11. 2. HEADSTOCK
The headstock is clamped on the left-hand side of
the bed.
The headstock spindle, a hollow cylindrical shaft
supported by bearings, provides a drive from the
motor to work-holding devices.
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Headstock (A gear-drive)
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12. 3. TAILSTOCK
The tailstock is made up of two units.
The top half can be adjusted on the base by two
adjusting screws for aligning the dead and live
centers for parallel turning.
The tailstock hand wheel
moves the tailstock spindle in
or out of tailstock casting.
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13. 4. CARRIAGE
The carriage supports the cutting tool and used to
move it along the bed of the lathe for turning
operations.
ti
Main parts of the carriage
are
1.SADDLE,
2.APRON,
2 APRON
3.CROSS-SLIDE
4. TOOLPOST
5. COMPOUND REST
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14. CUTTING TOOLS ANGLES
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15. TYPES OF LATHE CUTTING TOOLS
# Left and Right-Cut Roughing Tools
# Finishing Tools
# Boring and Inside Threading Tools
# Facing Tools
# Round-Nose Turning Tools
# Threading Tool
# Parting Tool
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16. Tool Materials
The hardness of a t l must b greater th th t of the material being machined.
Th h d f tool t be t than that f th t i lb i hi d
# Nature of the finished product.
# Type of operation
operation.
# Volume of production.
# Tool design details.
# Condition of tool.
# Type of material being machined.
CARBON STEEL TOOLS
# Are characterized by low hot hardness and poor hardenability.
# Carbon contents range from 0.8 percent to 1.3 percent.
# Tools of this type can be used for light work where temperatures produce do not
exceed 204°C (400°F).
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17. Medium-Alloy Steels
# These steels are not satisfactory for operations where high temperatures are
encountered, as in high production.
# In finishing operations, they can be used successfully
High-Speed Steels
# Are characterized by superior wear resistance and hot hardness.
# It contain up to 18 percent tungsten and 51.5 percent chromium as the
principal alloying elements.
# Other alloying elements such as Mo & Co give special qualities.
# These cutters will retain keen cutting edges at temperatures up to 593°C .
Cast Alloys
# A number of nonferrous alloys known as stellites have been developed for use
as cutting tools,
tools
# These alloys usually contain 2 to 4 percent carbon, 14 to 29 percent tungsten, 27
to 32 percent chromium, 40 to 50 percent cobalt.
# The tools must be used as cast and cannot be heat-treated.
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18. Cemented Carbide
# Are known by trade names such as Carboloy® Kenna-metal®, Vascoloy
Carboloy®, Kenna metal® Vascoloy-
Ramet®, and Pirthite®.
There are two general grades cemented carbides in use:
(1) The "C" grade is made up of tungsten carbide with cobalt as a binder.
This grade is used in machining cast iron and nonferrous metals.
(2) The "S" grade is made up of tungsten titanium and tantalum carbides with
S tungsten, titanium,
cobalt as a binder. This grade is used on steels.
# The cobalt content may vary from 3 percent to 16 percent.
Cemented carbides have the following characteristics:
(1) High hardness over a wide range of temperatures.
(2) High thermal conductivity
(3) Low thermal expansion
(4) Stiffness.
# Cemented carbide should be used at much higher operating EN
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speeds than high-speed steel tools.
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19. TOOL FAILURE
There are many factors that can contribute to the failure of a cutting tool The
tool.
following are a few of these factors:
(1) Temperature failure.
(2) Fracture of the tool point.
(3) Tool wear
Temperature Failure
The heat generated at the cutting edge of the tool may become excessive The
excessive.
heat will cause the tool to soften. Tool failure will occur. This type of failure occurs
quite rapidly after a certain temperature is reached.
Fracture of Tool Point
Because of their hardness, carbide-tipped tools are mechanically brittle and weak.
Cutting forces may be too great for a given tool. This will cause small portions of
the tip to break away In some instances the whole tip may be destroyed If the
away. instances, destroyed.
tool or work is not properly supported, vibration and chatter may occur. These can
cause tool point to fracture.
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20. Tool Wear
Tool wear can be attributed to two basic causes:
(1) Wear due to plowing or abrasive action of the carbides or other hard
particles in the work piece.
(2) Wear resulting from instantaneous "welds" that occur when the chip and
finished surface slide over the tool face
LATHE TOOLHOLDERS AND TOOLPOSTS
Lathe cutting tools are generally held by two methods:
(1) In tool holders, which provide a means of rigidly holding the cutting tool.
(2) In tool posts, which provide a means of holding either a tool holder or a
cutting tool.
The most common are the standard (round), turret, heavy-duty (open-side), and
quick-change tool posts
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21. Tool Holders Types
Following are the tool holders types:
1. Tool holders for High Speed Steel (HSS) Tool bits
2. Tool holders for Brazed Carbide Tipped Tool bits
3. Cutting Off Tool holders
4. Threading Tool holders
5. Boring Tool holders
Tool Posts Types
Following are the tool holders types:
1. Standard (Round) Tool post
2. Turret Type Tool post
3. Quick Change
3 Quick-Change Tool post
a. Dovetailed tool post
b. Boring Bar holder
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22. WORK HOLDING DEVICES
1.
1 With the faceplate.
faceplate
2. With the lathe dog.
3. With the lathe chuck
4. With the collet chuck.
- This is independent chuck
- For holding cylindrical generally has four jaws , which are
- St k centered
Stock t d adjusted individually on the chuck
face by means of adjusting screws
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Three-Jaw Universal Chuck Four-Jaw Independent Chuck
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23. iece
# Work pieces can be bolted to the faceplate.
Workpi
W
Faceplates
Collet chuck is used to hold
small work pieces
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24. Drill h k ith tapered shank t fit tailstock
D ill chuck with a t d h k to t il t k
LATHE DOG
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25. CUTTING SPEED AND FEEDS
CUTTING SPEED
Cutting speed for lathe work may be defined as the rate at which a point on the
circumference of the work passes the cutting tool in a minute.
Cutting speed may be expressed in feet per minute (ft/min) or meters per minute
(m/min).
Inch Calculations Metric C l l ti
M t i Calculations
CS ( ft ) x12 CS x 320
r / min  r / min 
 x work dia.(in.) D (mm)
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26. Lathe Feed
The feed of a lathe is define as the distance the cutting tool advances along
the length of the work for every revolution of the spindle.
Cutting Time =
length of cut
l h f
feed x r/min
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Speed, feed, and depth of cut in turning. E N
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27. MACHINING OPERATIONS
1.FACING
1 FACING
FACING
2.TURNING
3.BORING
4.TAPER TURNING
5.CHAMFERING
TURNING
6.THREADING
7.DRILLING BORING
8.REAMING
9.TAPPING
10.COUNTER SINKING
11.COUNTER BORING
12.PARTING EN
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13.KNURLING
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28. TAPPING
THREADING
TAPER TURNING
DRILLING & REAMNING
CSK & C’BORE
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