M.P- II-UNIT II CENTRE LATHE AND SPECIAL PURPOSE LATHES..ppt

Manufacturing Process - II

1. UNIT -2
CENTRE LATHE AND
SPECIAL PURPOSE
LATHES

2. INTRODUCTION
•Latheisthemostimportantmachineusedinany
workshop.likefromsmallscaleindustrytolarge
scaleindustry.
•ALatheremovesmetalfromrotatingtheworkpiece
byusingsinglepointcuttingtool.
•Thepartstomachinedcanbeheldb/wtworigid
supportscalledliveanddeadcentre's.
•Thetoolismovedperpendiculartoworkpieceaxisto
produceaflatsurface.
•Thetoolismovedatanangletoworkpieceaxisto
producetaperedsurface.

3. VARIOUS OPERATIONS
The following operations can be done
by using lathe. There are: turning,
taper turning, eccentric turning,
chamfering, facing, drilling, boring,
reaming, tapping, knurling, forming,
grooving, polishing, spinning and
thread cutting.

4. OLDEN DAYS LATHE -WOOD WORK

6. .

7. PARTS OF A LATHE
•BED
•HEAD STOCK
•TAIL STOCK
•CARRIAGE
•FEED MECHANISM

8. LATHE BED
Its the base of the
machine.
Its made up of
cast iron alloyed
with nickel and
chromium.
It has v and
dovetail guide
ways.

9. Lathe bed
Accurately machined
slideways
Slidewaysguide carriage
& tailstock
Headstockon upper end
of the lathe bed

10. Head stock
Headstock
Holds lathe spindle
and gears
Chuckis fitted to
spindle
Spindleis hollow for
long bars
Its having driving and
speed changing
mechanism
A live centre is
attached to the spindle
in the head stock.
So its called live centre

11. Tailstock
Can be moved along
slideways
Can be clamped
in any location
Inside tapered
to hold drill chuck

12. .

13. Carriage
Moves along bed
between tailstockand
headstock
Saddle–across the
lathe
Apron–hangs down
in front

14. /
•.

15. .
•Feed shaft
Used to move the
Carriage
automatically
•Lead screw
Used when screw
cutting on the
lathe

16. Cross slide
Fitted on the Saddle
Moves cutting tool at
right angles to lathe
bed

17. Top Slide (Compound slide)
Fitted to top of Cross slide
Carries toolpost and cutting
tool
Can rotate to any angle
Is used to turn tapers

18. Chucks
•Three Jaw Chuck
Self centring
Holds round and
hexagonal work
3 jaws are connected
Jaws are stamped 1,2 & 3
and fitted in order
Chuck key used to open

19. Tool post
Fitted on top slide and
carries the cutting tool
or the cutting tool
holder
Can adjust the height
on some types
Can carry 4 different
tool holders

20. Types of tool post
SIGLE SCREW
TOOL POST

21. Open side tool post

22. Four way tool post

23. Four bolt tool post

24. SPECIFICATION OF LATHE

25. SPECIFICATION
The size of the lathe
specified as follows
•Length of bed
•Distance b/w centers
•Height of centers from bed
•Swing over the bed
•Width of the bed
•Spindle bore
•Spindle speed
•Swing over the cross slide

26. Types of lathe

27. Lathe types
SPEED LATHE
(a) wood working lathe
(b) Metal spinning lathe
(c) Metal Turning Lathe
(d) Polishing Lathe
ENGINE LATHE
(a) step cone pulley drive lathe
(b) Geared Lathe
(c) Variable speed Lathe
BENCH LATHE
TOOL ROOM LATHE
SEMI AUTOMATIC LATHE -
(a)Capstan Lathe
(b)Turret Lathe
AUTOMATIC LATHE
SPECIAL PURPOSE LATHE
Crank shaft lathe , Wheel Lathe ,
Duplicating Lathe
COPYING LATHE

28. 1. SPEED LATHE
It’s a simplest lathe.
It consist of head stock , bed ,tailstock and
adjustable slides.
It can be operated at various speeds.
The speed range is from 1200 –3600 rpm.
Used for wood working, spinning and
polishing

29. SPEED LATHE -Spinning in lathe

30. ENGINE LATHE
•In earlier days it was driven by steam engine
and hence its called engine lathe
•It has lead screw , feed rod , head stock ,
speed change gears and everything provided.
•Its used for turning, taper turning , threading,
drilling, knurling, reaming and forming.

31. 2. ENGINE LATHE or CENTRE LATHE

32. 3. BENCH LATHE
Its mounted on a bench
It’s a small size lathe for small and accurate machining operations.

33. 4.TOOL ROOM LATHE
It consist of all necessary attachments
required for precision and accurate
machining.
It has more variety of speed and feed
ranges
It has taper turning attachments, quick
change gear mechanism, steady rest,
coolant pump, micrometer stop… etc
This lathe is costly due to its high
precision and accuracy in operation.

34. 5.SEMI AUTOMATIC LATHE
Some operations done
manually and some
operations done
automatically
Example : capstan and turret
lathe
Its mainly used for mass production
It has heavier head stock, more speed and feed
For certain usage they removed the tail stock and mounted a turret head
For mass production–they using two tool post along with turret head

35. Automatic lathe
All the operations are done automatically
( Loading ,unloading and tool changing )
It has a cam shaft with number of cams
used to change the feed , speed and tool
in the operation.
Its mainly used in mass production.
Initial setting only done by worker. So one
operator can work more than one
machine at a time.
So machining time is less.

36. SPECIAL PURPOSE LATHE
•For doing some special type of products in
operations we need some extra set up in the
lathe. That kind of special set up lathe is called
special purpose lathe.

37. COPYING LATHE
•The tool in the lathe follows a template through a tracer.
•The tracer is connected to the cutting tool through cutting devices.
•According to the tracer movement, the tool moves to machine the job.

38. HEAD STOCK MECHANISM
1. Back geared mechanism
2. All geared mechanism

39. 1. Back geared mechanism
For having slow speed running in spindle in tread cutting and knurling
we go for back geared mechanism

40. Working of back geared head stock
•For normal operation the bull gear is locked with
pulley
•For having slow speed the lock is released and the
lever L is pulled to connect B1 with pulley pinon.
•So now the power moves from P1 to B1 and then B2
to P2
•Like wise the speed is reduced.

41. ALL GEARED HEAD STOCK
•It give wide range of speeds
•Its more efficient and compact than cone pulley mechanism
•Power available at the tool is almost constant for all spindle speeds
•Belt shifted is eliminated.
•The vibration in the spindle is reduced
•More power can be transmitted.

42. ALL GEARED HEAD STOCK

43. FEED MECHANISM
•Feed is defined as the movement of tool
relative to the work
•This feed mechanism used to transmit power
from spindle to the carriage.
•It convert rotary motion of spindle in to linear
motion of table

44. Types of feeds
•Longitudinal feed : Tool movement parallel to lathe axis
This is for moving carriage
•Cross feed : The movement of tool perpendicular to lathe
axis
This is for movement of cross slide
•Angular feed : The tool movement at an angle to lathe axis
This is for the movement of compound rest

45. TUMBLER GEAR
MECHANISM
•Used to change the direction of feed rod and
lead screw

46. working
•Ithasthreeleverpositioninitsarrangements.
thegearAandBareinabracket.
•BychangingthepositionofleverthegearAorB
goingtoconnectwiththespindlegear.
•IfgearAconnectedwithspindlegearmeans,the
rotationalpowermovesfromspindlegearC-A–D–
E–Fofleadscrew.Heretheleadscrewrotatessame
tospindledirection.Sothecarriagewillmovefrom
lefttoright.
•IfthegearBconnectswithspindlegearcthenthe
rotationalpowertransmittedfromC-B–A–D-E-F.
Heretheleadscrewrotatesoppositetospindle
direction.Sothecarriagewillmovefromrighttoleft

47. TUMBLER GEAR REVERSING MECHANISM

48. Quick change gear box
•Its used to get various power feedin the lathe.
•Power from spindle shaft transmitted to feed shaft through
tumbler gear, change gear train and quick change gear box.
•Shaft A has different sizes of gear keyed with cone gear.
•Shaft B receives 9 speeds from shaft A.
•Then gear B connect with gear Cby sliding gears. Here there
are 4 cone gears .
•So we get 9 x 4 = 36 speeds
•The shaft cis connected to lead screw by a clutch for the
application of thread cutting.
•And feed rod connected by gear train for automatic feed
movement.

49. Quick change gear box

50. Tumbler gear quick change gear box
•It’s the simplest form of quick gear box
•The different speed of the driving shaft
obtained by tumbler gear and cone gear
arrangement.
•The driving shaft has many cone gears and the
driven shaft has sliding gears.
•The sliding gears are keyed to driven shaft
which is connected to lead screw or feed rod.
•By sliding the gears through tumbler gear we
get different speeds.

51. Tumbler gear quick change gear box

52. Apron Mechanism
•Its used to transferring the rotary motion of
lead screw or feed rod into feed motion of the
carriage.

53. Apron Mechanism

54. working
•The lead screw and feed rod get power from spindle.
•Power transmitted from feed rod to the worm wheel through
gears A,B,C,D and worm
•A splined shaft is attached to the worm wheel. This shaft
always engaged with gear F and G which is keyed to feed
check shaft.

55. WORK HOLDING DEVICES
•CHUCKS
•CENTRES
•FACE PLATE
•ANGLE PLATE
•MANDRELS
•STEADY AND FOLLOWER REST

56. WORK HOLDING DEVICES
-CHUCKS
•Its used to hold work piece of small length and
large diameters (L< 4D)
•Its also used to hold irregular jobs
•The chuck is attached to the headstock spindle
of the lathe.
•Types -3 jaw –self centering
-4 jaw –independent centering
-Magnetic chuck

58. 3 jaw chuck
•It’s a self centering type of internal
mechanism chuck.
•All the three jaws moves at a same time to
hold cylindrical jobs.

59. 4 jaw chuck
•Each jaws moves separately
•It has a slot at the back, when the key is
turned the jaw move separately.
•So we can easily hold the irregular jobs
•These jobs also used to hold the hollow
work pieces by reversing its position

60. ColletChuck
•Collet chuck is used to hold small workpieces.
•Used for high-precision work
•Spring collets available to hold round,
square, or hexagon-shaped workpieces
•Each collet has range of only few
thousandths of an inch over or under size
stamped on collet

62. Magnetic chuck
•It’s a easiest way of catching the work piece in
the chuck.
•The plates are electro magnetized during the
process.
•So its only used for Magnetic material only

63. WORK HOLDING DEVICES
-CENTRES
•The long shafts can be held between the
centers.
•Catch plate and dog carrier is used to hold the
job between centers.
•The live center in the head stock and dead
center in the tail stock are used to hold the
work piece.
•A small drill is made in the work piece ends for
having perfect contact of centers with work
piece.

64. Centres

65. CENTRES

66. Dead centre
•Fits in the tailstock spindle, remains
stationary while the work rotates on its
point

67. •It’s a circular cast iron disc with 4 T-Slots and
number of plain radial slots.
•These slots used to holt the w/p by clamps
and bolts.
•Its highly efficient to hold asymmetrical work
of complex and irregular shape work piece.
•When the spindle rotates, the face plate will
also be rotated and the work will rotate.
WORK HOLDING DEVICES
-FACE PLATE

69. FACE PLATE

70. •Its a perfectly machined faces right angled to
each other, made up of cast iron block.
•It has slots and holes in the faces.
•So one of the face is mounted on face plate
and the work piece is mounted on other face.
•Counter weights are fixed to balance the
weight of the w/p , when its fixed eccentrically
as shown in figure.
•Its mainly used to hold the elbow pieces.
WORK HOLDING DEVICES
-ANGLE PLATE

72. ANGLE PLATE

73. •Its used to hold the hollow pieces
•The inside diameter of the w/p is equal to the
outside diameter of the w/p.
•The work mounted with the mandrel is held
between the centers.
WORK HOLDING DEVICES
-MANDRELS

74. PlainMandrel

75. ExpandingMandrel

76. GangMandrel

77. StubMandrel

78. MANDREL

79. Lathe Dogs/Carrier
•A lathe dog ( lathe carrier) is a device that clamps
around the workpiece and allows the rotary motion of the
machine's spindle to be transmitted to the workpiece.
•A carrier is most often used when turning
between centers on a lathe.

80. Types of LatheDogs
•Standard bent-tail lathe dog
–Most commonly used for round workpieces
–Available with square-head setscrews of
headless setscrews
•Straight-tail lathe dog
–Driven by stud in driveplate
–Used in precision turning

81. Types of LatheDogs
•Safety clamp lathe dog
–Used to hold variety of
work
–Wide range of adjustment
•Clamp lathe dog
–Wider range than others
–Used on all shapes

82. Work Held BetweenCentre

83. Work Held BetweenCentres

84. •Its fixed in the bed of the lathe by clamp and
bolts
•The w/p is supported by 3 jaws of the
arrangement.
•The longer work pieces are machined using
this type of arrangements.
•We can fix the steady rest any where in the
lathe bed according to the length of the job.
WORK HOLDING DEVICES
-STEADY REST

85. SteadyRest

86. SteadyRest

87. STEADY REST

88. •Its mounted on the saddle.
•So when the carriage with the tool moves ,
the set up also moving along the w/p.
•So it give continuous support to the work
piece.
WORK HOLDING DEVICES
-FOLLOWER REST

89. FOLLOWER REST

90. Tool holders
Used for holding
cutting tool bits
Available in Right
hand, left hand and
straight

91. •Cutting Tools
Can be High Speed
Steel held in tool
holders
Can be also Ceramic
(Tungsten carbide)
bits held directly in
toolpost

92. Facing
operation

93. facing

94. Parting off
•If the workers wants to cut
off the part they have
turned, they can use the
hacksaw and a vice or use
the parting off tool on the
lathe.

95. Screw-cutting on the lathe
•Lathes are also used
to cut threads in
round bars
•These threads take up
different profiles e.g
iso (60°) ACME etc.
•These threads can be
seen on bench vices,
lathes etc.

96. LATHE OPERATIONS
.
Producing a
Cylindrical Surface
Taper Turning
Producing a Flat Surface

97. Drilling on a Lathe
Parting Off / Under Cutting
Radius Turning Attachment

98. Taper
turning

99. HOW TO CENTRE THE CUTTING TOOL

100. TWO TYPES OF LATHE CUTTING TOOLS

101. Tools

102. DRILLING WITH THE CENTRE LATHE
USING THE TAILSTOCK FOR DRILLING

103. .

104. Using twist drill

105. TURNING A LONG TAPER

106. Taper turning

107. Taper turning
offsetting the tailstock

108. HOW TO USE A KNURLING TOOL

110. TAPER TURNING

111. TAPER TURNING
•Its defined as a uniform change in the diameter of the work
piece measured along its length
•It’s a process of making conical surface along the cylindrical
work piece
•D –Larger diameter of the taper
•d -Small diameter of the taper
•L –length of the tapered part
•Α–Half taper Angle
CONICITY , K = (D-d) / L

112. Measuring instruments
To estimate the power the following instruments are required
•Dynamometer
•Ammeter
•Wattmeter
•Calorimeter
•Thermo Couple
Among these mostly we are using dynamometer for measuring
cutting force

113. 48
SettingSpeedsonaLathe
•Speeds m e a s u r e d in revo utions per
minute
–Changed by stepped pulleys or gear levers
•Belt-driven lathe
–Various speeds obtained by changing flat belt
and back gear drive
•Geared-head lathe
–Speeds changed by moving speed levers into
proper positions according to r/min chart
fastened to headstock

114. SEMI AUTOMATIC
LATHES
-CAPSTAN LATHE
-TURRET LATHE

115. INTRODUCTION
•In ordinary lathe the tool changing and setting will take more time,
so the total production will be affected.
•So to minimize cost of production , we going to introduce some
special lathe called semi automatic lathe.
•Here the tool are preset. More than one tool used to complete the
work in the job
•So during machining the tool changing and setting time is minimized.
So its suitable for mass production
•In semi automatic machine loading and un-loading of work piece ,
bringing the tool to require position, coolant on off, selecting
require spindle speeds are done manually.The tool changing done
automatically.
•Capstan and turret lathe are the two types of semi
automatic lathe

116. Capstan and turret lathe

121. PARTS
•Capstan lathe –for small and light duty work
•Turret lathe –for heavy duty lathe
MAIN PARTS
Bed
Head stock
Cross slide
Turret head and saddle
Preset stops or Feed stops rods

122. Bed
It’s a heavy base , over this we have all other parts
Cross slide
it has two types
1.Reach over type –its mounted on bed guide ways b/w head
stock and turret. It has two tool post. One is at the front
having four faces of square turret for mounting tools. Each
tool can be rotated to 90 degree . Stop bars are used to
control the movement of tools. The tool can move in
perpendicular and parallel to spindle axis
Rear post having parting off tool only
2. slide hung type
This has no rear post . It has great swing . So it can do work on
larger diawork piece

123. .
•Head Stock
Turret and capstan lathe having heavy and larger head stock and
powerful motor of 30 –2000 rpm speeds is fitted
Types
1. Step cone pulley driven head stock
2. Direct electric motor driven head stock
3. All geared head stock
4. Pre selective Head stock –It has a friction clutches.
so we can do rapid stopping and starting . Also speed changing
for different machining operations can be done by simply
pushing a button or pulling a lever.
The required speed of the next operation can also be selected
in advance

124. .
•Turret Head
It’s a hexagonal block having six faces with a bore for mounting
six or more than six tools at a time. The turret head is
mounted on a ram on a saddle. The forward movement of
ram is controlled by a preset adjustable stop.
To index the cutting tool, the ram or turret is returned to its
starting position for tripping the stops.
Each tool is indexing to
60 degree by the
rotation of circular plate.

126. .
•Saddle
In Capstan Lathe –Turret head
mounted on ram which is slides on
saddle.
In Turret Lathe -Turret head
mounted directly on saddle. Which
slides bed ways during machining

128. Geneva Mechanism
•It’s a automatic indexing type to index the turret by 1/6 of a
revolution, the ram is returned to the starting position.
•Then the next tool comes into position to perform the
machining operation
•Turret head, an index plate , a bevel gear and ratchet are
mounted on the same vertical spindle of the saddle. A spring
actuated plunger is used to lock the index plate which
prevents the rotation of turret during machining.
•When turret trips the stop, the plunger is released with the
help of spring loaded cam and a pin already fitted with
plunger. So the index plate is free to rotate
•Then the indexing pawl is engaged with ratchet and rotates
1/6 or 60 deg. Of revolution. When the turret moves forward,
again the plunger locks the index plate.

129. Geneva Mechanism or
Indexing Mechanism

130. Bar Feeding Mechanism
•The bar feeding mechanism used to supply the work piece.
•In capstan and turret lathes, the bar is fed automatically without
stopping the lathe which reduces the production time
•The bar stock passes through a chuck and hollow spindle of the
lathe. The bar is fitted with the bar chuck by set screws.
•The chuck rotates in a sleeve along with bar. The loose sleeve is
housed on a sliding bracket which slides over a sliding bar.
•Its again attached to one end of a chain.
•A suspended weight is hanging at the other end of a chain to exert
a constant force on the bar chuck towards right.
•When the bar is released by the collet, the force due to weight will
feed the work towards right.
•It continues till the work piece butts against the bar stop held in
the turret. Then the collet is closed

131. Bar Feeding Mechanism

132. Difference
S.NO Capstan Lathe Turret Lathe
1Turret head is mounted on a ram,
which slides on saddle
Turret head is directly mounted on
saddle, which slides on bed
2Turret movement is limited Turret moves on the entire length of the
bed without any restriction
3So shorter workpiece can be
machined
Longer work piece can be machined
4Less rigidity More rigidity
5Only for light duty operationsUsed for heavy duty operations
6Only 60 mm diawork piece only
machined
125 -200mm diawork piece only
machined
7No cross wise movement to turretFor facing and turning operation there is
a cross wise movement
8 Turret head moved manually Turret head moved automatically
9Over hung type of cross wise not
used
For some specific operations overhung
used

133. TOOL HOLDING DEVICES
•Various types of tool holders are fitted in hexagonal turret ,
front tool post and rear tool post.
1.Straight cutter tool holder
2.Adjustable angle cuter tool holder
3.Multiple cutter holder
4.Offset cutter holder
5.Sliding tool holder
6.Knee tool holder
7.Flange tool holder
8.Roller steady box tool holder
9.Combination tool holder
10.Self opening type die holder
11.Knurling tool holder
12.Collapsible taps
13.Tap holder

134. 1. Straight cutter tool holder

135. 2.Adjustable angle cuter tool holder

136. 3.Multiple cutter holder

137. 4.Offset cutter holder

138. 5.Sliding tool holder

139. 6.Knee tool holder

140. 7.Flange tool holder

141. 8.Roller steady box tool holder

142. 9.Combination tool holder

143. 10.Self opening type die holder

144. 11.Knurling tool holder

145. 12. Collapsible taps

146. 13. Bar Stop

147. AUTOMATIC
LATHE

148. INTRODUCTION -Automats
Automatic lathe or simply automats are the machine tool in
which all operations are required to finish off the work piece
are done automatically without the attention of an operator
All the operations including loading and unloading are done
automatically
By using the control system , all the working and idle operations
are performed in a definite sequence

149. Advantages of Automatic Lathe over
conventional lathe
1.Mass production of identical parts
2.High accuracy is maintained
3.Production time minimized
4.Less floor space required
5.Unskilled labour is enough. So labour cost minimized
6.Constant flow of production
7.One operator can supervise more than one machine .
8.The bar stock is fed automatically

150. Classification of Automats
1. According to the type of work material used
a)Bar stock Machine
Bar type of work materials are machined to produce screws ,
nuts, rings, studs etc. collects are used to hold the work piece
b) Chucking Machine
blank type of components are produced in this machine. the
components are held in jaw chuck or special fixtures

151. Classification of Automats
2. According to the number of spindles
a)Single spindle Automats
These machines having only one spindle. So one component
can be machined at a time
EXAMPLE : Automatic cutting off machine
Automatic Screw Cutting Machine
Swiss Type Machine
b) Multi Spindle Automats
These machines have 2 to 8 spindles. operators performed
simultaneously in all spindles. So the rate of production is high
TYPES –Parallel Action Type
Progressive Action Type

152. Classification of Automats
•According to the arrangements of spindles
a)Horizontal spindle
The spindles are in horizontal position. These are
used to machine lengthy work piece with small dia.
b) Vertical Spindle
Here the spindles are in vertical position. These
machines are heavier and stronger.
Used to machine larger diameter & small length
work pieces

153. Classification of Automats
•According to the feed control
a) Single cam shaft rotating at constant speed
Here a single cam control the working and idle motion of the
tool. Both the things are happened at same time
b) Single cam shaft with two speeds
The cam rotate at slow speed at working motion. And rotates
faster speed during idle motion. So the idle time is reduced.
c) Two cam shaft
(i) Main Cam Shaft –Tool movement during working are
controlled by main cam shaft . It rotates at slow speed
(ii) Auxiliary Cam shaft –The tool movement during idle
motion is controlled by auxiliary cam shaft. Here the cam shaft
rotes at faster speed. So idle time is reduced.

154. Classification of Automats
•According to the Use
a)Single Purpose Machine
This machine is designed to produce single component of
fixed shape and size.
b) General Purpose Machine
This machine is designed to produce variety of components
with slight variations in shape and size

155. SINGLE SPINDLE AUTOMATIC LATHE

156. Automatic Screw cutting machine

157. Automatic Screw cutting machine
•This is also called turret type automatic screw cutting machine .
Because it has turret head.
•This machine is used for producing small screws of all types
•We can do internal and external operations in this machine like
drilling , reaming , boring , spot facing, threading, tapering,
turning , forming and under cutting.
•It has one cam shaft with 3 plates of cam for
controlling the movement of front tool post , rear tool
post and top tool post.
•The turret head movement is controlled by lead cam.
It give slow forward and slow return to the turret.

158. Parts to be Produced in
Automatic Screw Cutting Machine

159. Swiss Type Screw Cutting Machine
•This machine is first developed in switzerland. So we
call it as Swiss type screw cutting machine.
•Its also called sliding head stock machine or movable
head stock machine.
•These machines are used to produce lengthy work
piece with small diameter ( 2 to 25mm)

160. Swiss Type Screw Cutting Machine

161. Features of
Swiss Type Screw Cutting Machine
1.Sliding head stock
2.A tool bracket having 4 to 5 tool slides
3.A special attachment called feed base
4.A cam shaft.

162. Swiss Type Screw Cutting Machine
1.Sliding Head Stock
The head stock has a collet. The bar stock
held in collet. The head stock slides along
the guide ways of the bed. A bell cam in the
cam shaft controls the sliding of head stock

163. Swiss Type Screw Cutting Machine
2.Tool Bracket
The tool bracket mounted on
the bed near to head stock.
It has 5 tool slides . Two
placed front and rear and
others placed radially.
The tools are moved front and
back in the guide ways.
The tool movement is
controlled by rocker arm and
plate cams.
The plate cams are placed in
the cam shaft

164. Swiss Type Screw Cutting Machine
3.Feed Base
•This is placed at the right of the lathe.
•Used to perform operations like drilling , boring , thread cutting
•The movement of this controlled by plate cams in cam shaft

165. .
•4.Cam shaft
This have bell cam and plate cams. Plate cams are used
to control the movement of tool posts.
WORKING
The bar stock is held in the rotating spindle by the collet.
The moving head stock give longitudinal feed to the w/p.
All the tools perform the operation at the same time.
one revolution of cam shaft produce one component.

166. Parts Producedin
Swiss Type Screw Cutting Machine

167. MULTI SPINDLE AUTOMATS

168. MULTI SPINDLE AUTOMATS
•They are having 2 to 8 spindles. The operation carried
out simultaneously in all spindles.
•So the rate of production is high
CLASSIFICATION
According to type of work piece
1.Bar type 2. Chucking type machine
According to the arrangements of spindles
1.Horizontal 2. Vertical spindle
According to the principle of operation
1. Parallel action 2. Progressive action

169. Parallel action Multi spindle Automatic
Machine
•Here the work piece is
finished in one working
cycle.
•Rate of production is high
•Suitable for producing
small parts of simple
shape from bar stock

170. Progressive actionMulti spindle Automatic Machine

171. Progressive actionMulti spindle Automatic
Machine
•The head stock has spindle carrier. And it rotates about
the horizontal axis of the machine
•There is one tool slide corresponds to each spindle.
•The tool slide move towards the work spindle during
machining
•During the indexing of spindle carrier the work is done
in every station.
•At the end of tools six station , the work is completed.

172. SPECIAL ATTACHMENTS FOR
LATHE

173. CENTRE LATHE MACHINE
ATTACHMENTS
173
•Toperformsomeunusualorspecificwork,somespecial
devicesorsystemsareadditionallyusedandmountedin
theordinarymachinetools.Suchadditionalspecialdevices,
whichaugmenttheprocessingcapabilityofanyordinary
machinetool,areknownasAttachments
•Taper turning attachment
•Copy turning attachments
•Milling and cylindrical grinding attachments
•Grinding Machine attachment For Lathe
•Spherical turning attachments
•Relieving attachment
•Thread Pitch Correction Attachment For Lathe
•Thread chase dial attachment
•Eccentric Turning attachment

174. Taper TurningAttachments
Crossslideisdelinkedfromthesaddleandismovedcrosswise
bytheguideblockwhichmovesalongtheguidebarpresetatthe
desiredtaperangle.
Thus,thecuttingtool,whichisfittedonthecrossslidethrough
thetoolpostandthecompoundslide,alsomovesalongwiththe
guideblockinthesamedirectionresultingthedesiredtaper
turning.
115

175. Mechanical Type Copy TurningAttachment
The entireattachment
175
ismountedonthe
after
cross
saddle
removingthe
slide from that.
The
replicating
template
thejob-
profiledesiredis
clampedatasuitable
positiononthebed.
Thestylusisfitted
inthespringloaded
toolslideandwhile
travelling
longitudinallyalong
withsaddlemovesin

176. Hydraulic type Copy TurningAttachment
176
Inmechanicalsystemtheheavycuttingforceis
transmittedatthetipofthestylus,whichcauses
vibration,largefrictionandfasterwearandtear.
Inhydrauliccopying,wherethestylusworkssimplyas
avalve–spoolagainstalightspringandisnot
affectedbythecuttingforce.
Herealso,thestylusmovesalongthetemplate
profile to replicate it on thejob.
Costlierthanthemechanicaltypebutworksmuch
smoothly andaccurately.

177. Hydraulic Type Copy TurningAttachment
118
Thecuttingtoolisrigidly
fixedonthecrossslide
whichalsoactsasavalve–
cum–cylinder.
Ifstylusremainsona
straightedgeparalleltothe
lathebed,thecylinderdoes
notmovetransverselyand
thetoolcausesstraight
turning.
Ifstylusstartsmovingalongaslopeorprofile,i.e.,incrossfeed
directiontheportsopenandthecylinderstartsmovingaccordingly
againstthepistonfixedonthesaddle.
Againthemovementofthecylinderi.e.,theslideholdingthetool,
isbysameamounttravelledbythestylus,whichclosestheports.
Repeating of such quick incremental movements of the tool, Δx and Δy
result in the profile with little surfaceroughness.

178. MillingAttachment
Thisisamillinghead,
comprisingamotor,asmall
gearboxandaspindleto
holdthemillingcutter,
mountedonthesaddleafter
removingthecrossslideetc.
areMillingattachments
generallyusedformaking
flatsurfaces,straightand
helicalgrooves,
longanddeep
splines,
screw
threads,wormsetc.incentre
lathesbyusingsuitablemilling
cutters.
178

179. Grinding
Attachment
Similar to milling attachment, but no gear box and the spindle speed is
much higher as needed for grinding operation.
Employedforexternalandinternalcylindricalgrinding,finishing
grooves,splinesetc.Andalsoforfinishgrindingofscrewthreadsin
centrelathe.
Cannot provide high accuracy and finish.
Called tool post grinder.
It is mounted on the compound rest in place of tool post.
Consists of a base plate, grinding wheel and a motor.
The job is held in a chuck or between centres.
It is extensively used for grinding lathe centres in position.
179

180. Spherical/Ball TurningAttachment
Spherical Turning with template
These simple attachments are used in centre lathes for
machining spherical; both convex and concave
surfaces and similar surfaces.
the desired path of the tool tip is controlled by the
profile of the template
which is pre-made as per the radius of curvature required.
The saddle is disconnected from the feed rod and the
leadscrew.
When the cross slide is moved manually in transverse

181. Spherical/Ball TurningAttachment
the distance R can be set according to the radius of curvaturedesired.
Spherical Turning withouttemplate

182. RelievingAttachment
Theteethofformrelievedmillingcutterslikegearmillingcutters,taps,hobs
etc.areprovidedwithflankhavingArchimedeanspiralcurvature.
Machiningandgrindingofsuchcurvedflanksoftheteethneedrelieving
motiontothetool(orwheel).
Itiscomprisedofaspringloadedbracketwhichholdsthecuttingtoolandis
radiallyreciprocatedonthesaddlebyaplatecamdrivenbythefeedrodas
indicated
182

183. Thread Pitch CorrectionAttachment
183
Whilecuttingscrewthreadincentrelathesbysinglepointchasingtool,oftenthe
actualpitch,p
adeviatesfromthedesired(orstipulated)pitch,p
sbyanerror(say±
Δp)duetosomekinematicerrorinthelathe.Mathematically,
p
s –p
a = ±Δp
Thereforeforcorrectpitch,theerror±Δpneedtobecompensatedandthismaybe
donebyasimpledifferentialmechanism,namelycorrectingbarattachmentas
schematicallyindicatedinFig.
Pa = 1 x U
C x L
±Δp = p
stan(±α).L/(πmZ)
where,U
C=transmissionratio,L=leadoftheleadscrew,m,Z=moduleandno.of
teethofthegearfixedwiththenutandisadditionallyrotatedslightlybythe
movementoftherackalongthebar.
Suchdifferentialmechanismofthisattachmentcanalsobeusedforintentionally
cuttingthreadwhosepitchwillbeessentiallyslightlymoreorlessthanthestandard
pitch,asitmayberequiredformakingdifferentialscrewshavingthreadsofslightly
differentpitchattwodifferentlocationsofthescrew.

184. Thread Pitch CorrectionAttachment
184

185. Thread Chasing DialAttachment
185
Cutting of threads is done in several passes and after each pass tool is
brought back to the initial start position for next pass
If the tool does not follow the path, the threads will be spoiled.
Thechasingdialovercomesthedifficultyofcatchingthethreadsat
correctstart.
Itconsistsofgraduateddialthatisconnectedtoawormwheel-The
wormisinmeshwiththeleadscrew,sothatifthesaddleis
stationary,theleadscrewactsasawormandrotatesthechasing
dial.
Whenthehalfnutisengaged,thetoolstartstravellingbutthedial
remainsstationarywithoneofthegraduationsoppositetothe
arrow.
Whenthecutiscompletedthesaddleisreturnedtothestarting
point.Whenthenutisdisengagedandthedialremainsrotatingas
soonasthegraduatedlinecomesoppositetothearrow,thehalf
nutcanbeengagedandthetoolwillfollowitsoriginalcut.

186. Thread Chasing DialAttachment
.
186

187. Eccentric TurningAttachment
187
.
Itreferstotheturningofcertaindiametersatdifferent
lengthsonthesameshaftorjobswhoseaxisisnotfalling
inlinewiththemainaxis.Acrankshaftofanengineisthe
exampleofsuchjob.
This type of attachment is equipped with the provision of
shifting the centres of the work away from the lathe spindle axis.
Anaccurate markingand truingis of
primeimportant in the
sequenceofoperationofjobsofthisnature.

188. TOOL LAYOUTS

189. Before starting the work, the following works are carried out
1.Selection of tools
2.Designing of special tools
3.Selection of speeds
4.Selection of feeds
5.Setting the require length of the work piece and tool travel length
These planning of operation in turret or capstan lathe is called Tool –Layout
THREE STAGES IN LAYOUT
1.Planning and scheduling
2.Detailed sketching and sequencing the operation
3.Sketching of work piece and tool movement
SIMPLE TOOL LAYOUTS

190. PROBLEM -1 -Prepare a tool layout of square headed bolt
from a square bar stock using a turret lathe

191. Stage -II

192. Stage –III –Tooling Schedule Chart

193. PROBLEM -2 -Prepare a tool layout of KNURLED SCREW
AND NUT as shown in fig . using a turret lathe

194. Stage –II –Tool layout prepared

195. Stage -III

196. .
.

197. SPECIAL ATTACHMENTS FOR
LATHE

198. CENTRE LATHE MACHINE
ATTACHMENTS
198
•Toperformsomeunusualorspecificwork,somespecial
devicesorsystemsareadditionallyusedandmountedin
theordinarymachinetools.Suchadditionalspecialdevices,
whichaugmenttheprocessingcapabilityofanyordinary
machinetool,areknownasAttachments
•Taper turning attachment
•Copy turning attachments
•Milling and cylindrical grinding attachments
•Grinding Machine attachment For Lathe
•Spherical turning attachments
•Relieving attachment
•Thread Pitch Correction Attachment For Lathe
•Thread chase dial attachment
•Eccentric Turning attachment

199. Taper TurningAttachments
Crossslideisdelinkedfromthesaddleandismovedcrosswise
bytheguideblockwhichmovesalongtheguidebarpresetatthe
desiredtaperangle.
Thus,thecuttingtool,whichisfittedonthecrossslidethrough
thetoolpostandthecompoundslide,alsomovesalongwiththe
guideblockinthesamedirectionresultingthedesiredtaper
turning.
115

200. Mechanical Type Copy TurningAttachment
The entireattachment
200
ismountedonthe
after
cross
saddle
removingthe
slide from that.
The
replicating
template
thejob-
profiledesiredis
clampedatasuitable
positiononthebed.
Thestylusisfitted
inthespringloaded
toolslideandwhile
travelling
longitudinallyalong
withsaddlemovesin

201. Hydraulic type Copy TurningAttachment
201
Inmechanicalsystemtheheavycuttingforceis
transmittedatthetipofthestylus,whichcauses
vibration,largefrictionandfasterwearandtear.
Inhydrauliccopying,wherethestylusworkssimplyas
avalve–spoolagainstalightspringandisnot
affectedbythecuttingforce.
Herealso,thestylusmovesalongthetemplate
profile to replicate it on thejob.
Costlierthanthemechanicaltypebutworksmuch
smoothly andaccurately.

202. Hydraulic Type Copy TurningAttachment
118
Thecuttingtoolisrigidly
fixedonthecrossslide
whichalsoactsasavalve–
cum–cylinder.
Ifstylusremainsona
straightedgeparalleltothe
lathebed,thecylinderdoes
notmovetransverselyand
thetoolcausesstraight
turning.
Ifstylusstartsmovingalongaslopeorprofile,i.e.,incrossfeed
directiontheportsopenandthecylinderstartsmovingaccordingly
againstthepistonfixedonthesaddle.
Againthemovementofthecylinderi.e.,theslideholdingthetool,
isbysameamounttravelledbythestylus,whichclosestheports.
Repeating of such quick incremental movements of the tool, Δx and Δy
result in the profile with little surfaceroughness.

203. MillingAttachment
Thisisamillinghead,
comprisingamotor,asmall
gearboxandaspindleto
holdthemillingcutter,
mountedonthesaddleafter
removingthecrossslideetc.
areMillingattachments
generallyusedformaking
flatsurfaces,straightand
helicalgrooves,
longanddeep
splines,
screw
threads,wormsetc.incentre
lathesbyusingsuitablemilling
cutters.
203

204. Grinding
Attachment
Similar to milling attachment, but no gear box and the spindle speed is
much higher as needed for grinding operation.
Employedforexternalandinternalcylindricalgrinding,finishing
grooves,splinesetc.Andalsoforfinishgrindingofscrewthreadsin
centrelathe.
Cannot provide high accuracy and finish.
Called tool post grinder.
It is mounted on the compound rest in place of tool post.
Consists of a base plate, grinding wheel and a motor.
The job is held in a chuck or between centres.
It is extensively used for grinding lathe centres in position.
204

205. Spherical/Ball TurningAttachment
Spherical Turning with template
These simple attachments are used in centre lathes for
machining spherical; both convex and concave
surfaces and similar surfaces.
the desired path of the tool tip is controlled by the
profile of the template
which is pre-made as per the radius of curvature required.
The saddle is disconnected from the feed rod and the
leadscrew.
When the cross slide is moved manually in transverse

206. Spherical/Ball TurningAttachment
the distance R can be set according to the radius of curvaturedesired.
Spherical Turning withouttemplate

207. RelievingAttachment
Theteethofformrelievedmillingcutterslikegearmillingcutters,taps,hobs
etc.areprovidedwithflankhavingArchimedeanspiralcurvature.
Machiningandgrindingofsuchcurvedflanksoftheteethneedrelieving
motiontothetool(orwheel).
Itiscomprisedofaspringloadedbracketwhichholdsthecuttingtoolandis
radiallyreciprocatedonthesaddlebyaplatecamdrivenbythefeedrodas
indicated
207

208. Thread Pitch CorrectionAttachment
208
Whilecuttingscrewthreadincentrelathesbysinglepointchasingtool,oftenthe
actualpitch,p
adeviatesfromthedesired(orstipulated)pitch,p
sbyanerror(say±
Δp)duetosomekinematicerrorinthelathe.Mathematically,
p
s –p
a = ±Δp
Thereforeforcorrectpitch,theerror±Δpneedtobecompensatedandthismaybe
donebyasimpledifferentialmechanism,namelycorrectingbarattachmentas
schematicallyindicatedinFig.
Pa = 1 x U
C x L
±Δp = p
stan(±α).L/(πmZ)
where,U
C=transmissionratio,L=leadoftheleadscrew,m,Z=moduleandno.of
teethofthegearfixedwiththenutandisadditionallyrotatedslightlybythe
movementoftherackalongthebar.
Suchdifferentialmechanismofthisattachmentcanalsobeusedforintentionally
cuttingthreadwhosepitchwillbeessentiallyslightlymoreorlessthanthestandard
pitch,asitmayberequiredformakingdifferentialscrewshavingthreadsofslightly
differentpitchattwodifferentlocationsofthescrew.

209. Thread Pitch CorrectionAttachment
209

210. Thread Chasing DialAttachment
210
Cutting of threads is done in several passes and after each pass tool is
brought back to the initial start position for next pass
If the tool does not follow the path, the threads will be spoiled.
Thechasingdialovercomesthedifficultyofcatchingthethreadsat
correctstart.
Itconsistsofgraduateddialthatisconnectedtoawormwheel-The
wormisinmeshwiththeleadscrew,sothatifthesaddleis
stationary,theleadscrewactsasawormandrotatesthechasing
dial.
Whenthehalfnutisengaged,thetoolstartstravellingbutthedial
remainsstationarywithoneofthegraduationsoppositetothe
arrow.
Whenthecutiscompletedthesaddleisreturnedtothestarting
point.Whenthenutisdisengagedandthedialremainsrotatingas
soonasthegraduatedlinecomesoppositetothearrow,thehalf
nutcanbeengagedandthetoolwillfollowitsoriginalcut.

211. Thread Chasing DialAttachment
.
211

212. Eccentric TurningAttachment
212
.
Itreferstotheturningofcertaindiametersatdifferent
lengthsonthesameshaftorjobswhoseaxisisnotfalling
inlinewiththemainaxis.Acrankshaftofanengineisthe
exampleofsuchjob.
This type of attachment is equipped with the provision of
shifting the centres of the work away from the lathe spindle axis.
Anaccurate markingand truingis of
primeimportant in the
sequenceofoperationofjobsofthisnature.