Manufacturing Processes

Mr. ANSAR A. MULLA
AUTOMOBILE ENGG DEPARTMENT
R.I.T. ISLAMPUR
- R.I.T. ISLAMPUR
1
AE 2091 – Manufacturing Processes
Chapter 04- Lathe, Drilling & Boring Machine

Contents
1. Lathe-Working principles, types,
2. specifications principal parts,
accessories and attachments
3. Drilling-Working principles, types,
specifications principal parts, accessories
and attachments
4. Boring Machine-Working principles,
types, specifications principal parts,
accessories and attachments
5. Various operations, boring tools and
bars, boring heads.
2

01 Lathe-Working principles, types, specifications
principal parts, accessories and attachments.
3
Working Principles
•commonly known as the mother of all
other machine tool.
•The main function of a lathe is to remove
metal from a job to give it the required
shape and size.
•lathe can be used to carry out other
operations also, such as drilling, reaming,
boring, taper turning, knurling, screw
thread cutting, grinding etc.
Working Principles

7
TYPES
1. Speed lathe
(a) Wood working
(b) Spinning
(c) Centering
(d) Po1ishing
2. Centre or engine lathe
(a) Be1t drive
(b) Individual motor drive
(c) Gear head lathe
3. Bench lathe
4. Tool room Lathe
5. Capstan and Turret 1athe
6. Special purpose lathe
(a) Whee1 lathe
(b) Gap bed lathe
(c) Dup1icating lathe
(d) T-lathe
7. Automatic lathe

Speed
lathe
Bench lathe
Tool room lathe
Turret lathe

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TYPES
1. Speed lathe
so named because of the very high speed of the headstock spindle.
2. Centre or engine lathe
I it was driven by steam engine.
Its headstock is much more robust in construction and contains additional
mechanism for driving the lathe spindle at multiple speeds.
Unlike the speed lathe, the engine lathe can feed the cutting tool both
in cross and longitudinal direction.
Classified according to methods of transmitting power to the machine.
belt, electric motor or through gears.

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TYPES
3. Bench lathe
small lathe usually mounted on a bench.
This is used for small and precision work.
4. Tool room Lathe
accurately built.
wide range of spindle speeds ranging from a very low to a quite high
speed up to 2500 rpm.
work on tools, dies, gauges and in machining work where accuracy is
needed.

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TYPES
vastly used for mass production work.
The distinguishing feature of this type of lathe is that the tailstock of an engine
lathe is replaced by a hexagonal turret,
several different types of operations can be done on a job without re-setting of
work or tools,
6. Special purpose lathe
(a) Whee1 lathe (b) Gap bed lathe (c) Dup1icating lathe (d) T-lathe
7. Automatic lathe
All the working and job handling movements of the complete manufacturing
process for a job are done automatically.
These are high speed, heavy duty, mass production lathes with complete
automatic control.

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TYPES
•A capstan lathe or a turret lathe is a production lathe used to manufacture any number of
identical pieces in the minimum time. These lathes are development of engine lathes. The
capstan lathe was first developed in the United States of America by Pratt and Whitney
sometimes in 1860.
•Special characteristics of a capstan or turret lathe enable it to perform a series of
operations such as drilling, turning, boring, thread cutting, reaming, chamfering, cutting-
off and many other operations in a regular sequence to produce a large number of identical
pieces in a minimum time.
•Capstan and Turret lathes are the examples of semi automatic lathes.

Sr. Capstan lathe Turret lathe
1 It is a light duty machine It is a heavy duty machine
2
The turret head is mounted on the ram and the
ram is mounted on the saddle.
The turret head is directly mounted on the
saddle and the saddle slides over the bed ways
3
The saddle will not be moved during
machining
The saddle is moved along with the turret head
during machining
4 The lengthwise movement of turret is less The lengthwise movement of turret is more
5 Short work pieces only can be machined. Long work pieces can be machined
6
It is easy to move the turret head as it slides
over the ram
It is difficult to move the turret head along with
saddle
7
As the construction of lathe is not rigid, heavy
cut cannot be given
As the construction of lathe is rigid, heavy cut
can be given
8
It is used for machining work pieces up to
60mm diameter
It is used for machining work pieces up to
200mm diameter
9 Collet is used to hold the work piece Jaw chuck is used to hold the work piece
10 The turret head cannot be moved crosswise
The turret head can be moved crosswise in some
turret lathes

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Principal Parts
Construction
1. Bed
2. Head stock
3. Tailstock
4. Carriage
5. Feed mechanism
6. Thread cutting mechanism
Principal Components of Central Lathe

20
Different parts of engine lathe or central lathe

21
principal parts
1. Bed
2. Head stock
3. Tailstock
Tail stock of central lathe.

22
principal parts
4. Carriage
5. Feed mechanism
1. End of bed gearing
2. Feed gear box
3. Lead screw and feed rod
4. Apron mechanism
6. Thread cutting mechanism
Tool post of centre lathe

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Accessories and Attachments
Lathe centres - Head & Tail
Carriers or driving dog and catch plates
Chucks
(1) Three jaws or universal
(2) Four jaw independent chuck
(3) Magnetic chuck
(4) Collet chuck
(5) Air or hydraulic chuck operated chuck
(6) Combination chuck
(7) Drill chuck.
Face plates
Angle plates
Mandrels
Rests
Lathe dog

Work Holding Devices
Lathe centers
Three jaws chuck Four jaws chuck
Collet chucks

Magnetic chuck Lathe dog
Angle plates
Face plate
Mandrel

Tool Holding Devices
Single tool holder
Four tool holder
Turret

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specifications

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specifications
The size of a lathe is generally specified by the following means:
(a) Swing or maximum diameter that can be rotated over the bed ways
(b) Maximum length of the job that can be held between head stock and tail stock centres
(c) Bed length, which may include head stock length also
(d) Maximum diameter of the bar that can pass through spindle or collect chuck of capstan lathe.
specify a common lathe machine
(i) Maximum swing over bed
(ii) Maximum swing over carriage
(iii) Height of centres over bed
(iv) Maximum distance between centers
(v) Length of bed
(vi) Width of bed
(vii) Morse taper of center
(viii) Diameter of hole through spindle
(ix) Face plate diameter
(x) Size of tool post
(xi) Number of spindle speeds
(xii) Lead screw diameter and number of threads per
cm.
(xiii) Size of electrical motor
(xiv) Pitch range of metric and inch threads etc.

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Operations
Operations, which can be performed
in a lathe either by holding the work
piece between centres or by a chuck
are:
1. Straight turning 2. Shoulder turning
3. Taper turning 4. Chamfering
5. Eccentric turning 6. Thread cutting
7. Facing 8. Forming
9. Filing 10. Polishing
11. Grooving 12. Knurling
13. Spinning 14. Spring winding

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Operations which are performed by holding the work by a chuck or a faceplate or an angle plate are:
1. Undercutting 2. Parting-off 3. Internal thread cutting 4. Drilling 5. Reaming 6. Boring
7. Counter boring 8. Taper boring 9. Tapping

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Operations
which are
performed by
using special
lathe
attachments are:
1. Milling
2. Grinding

Work holding Devices
 Various work holding attachments such as three jaw chucks, collets, and centers can be
held in the spindle.
 Work is held in the lathe with a number of methods,
 Between two centres.
 The work piece is driven by a device called a dog; this method is suitable for parts with
high length-to-diameter ratio.
 A 3 jaw self-centering chuck is used for most operations on cylindrical work-parts. For
parts with high length-to-diameter ratio the part is supported by center on the other end.
 Collet consists of tubular bushing with longitudinal slits. Collets are used to grasp and
hold bar stock. A collet of exact diameter is required to match any bar stock diameter.
 A face plate is a device used to grasp parts with irregular shapes.

Fig : Various types of mandrels to hold work pieces for turning. These mandrels are
usually mounted between centers on a lathe. Note that in (a) both the cylindrical
and the end faces of the workpiece can be machined, whereas in (b) and (c) only
the cylindrical surfaces can be machined.
Mandrels

 Work to be turned between centers must
have center hole drilled in each end
 Provides bearing surface
 Support during cutting
 Most common have
solid Morse taper shank
60º centers, steel with carbide tips
 Care to adjust and lubricate occasionally
Lathe Center

 Used extensively for holding work for machining operations
 Work large or unusual shape
 Most commonly used lathe chucks
 Three-jaw universal
 Four-jaw independent
 Collet chuck
Chucks

Three-jaw Universal Chuck
 Holds round and hexagonal work
 Grasps work quickly and accurate within few thousandths/inch
 Three jaws move simultaneously when adjusted by chuck wrench
 Caused by scroll plate into which all three jaws fit
 Usually has three jaws which move in unison as an adjusting pinion is rotated.
 The advantage of the universal scroll chuck is its ease of operation in centering
work for concentric turning.
 This chuck is not as accurate as the independent chuck, but when in good
condition it will center work within 0.002 to 0.003 inches of run out.

Four Jaw Independent Chuck
 Used to hold round, square, hexagonal, and irregularly shaped work pieces
 Has four jaws
 Each can be adjusted independently by chuck wrench
 Jaws can be reversed to hold work by inside diameter

TYPES OF CHUCK
Three jaw chuck
- Forholding cylindrical stock
centered.
- For facing/center drilling,etc.
Four-Jaw Chuck
- This is independent chuck
generally has four jaws , which are
adjusted individually on the chuck
face by means of adjusting screws

Collet Chuck
Collet chuck is used to hold
small workpieces
Magnetic Chuck
Thin jobs can be held by
means of magnetic
chucks.

(a) and (b) Schematic illustrations of a draw-in-type collets. The workpiece is placed in the collet hole,
and the conical surfaces of the collet are forced inward by pulling it with a draw bar into the sleeve. (c)
A push-out type collet. (d) Workholding of a part on a face plate.
Chucks
usually equipped with 3 or 4
jaws
3 jaw chucks generally are
self centering. Used for
round work pieces.
Can be centered within
.025mm independently.
4 jaw chucks are for
square, rectangular, or odd-
shaped work pieces
Can be power actuated
Work holding Devices

46-42
Headstock Spindles
Universal and independent
chuck fitted to three types
of headstock spindles
1. Threaded spindle nose
 Screws on in a
clockwise direction
2. Tapered spindle nose
 Held by lock nut
that tightens on chuck

46-43
Headstock Spindles
3. Cam-lock spindle nose
• Held by tightening cam-
locks using T-wrench
• Chuck aligned by taper
on spindle nose
Registration lines on spindle nose
Registration lines on cam-lock
Cam-locks
Cam-lock mating stud on
chuck or faceplate

Collet Chuck
 Most accurate chuck
 Used for high-precision work
 Spring collets available to hold round, square, or hexagon-shaped work pieces
 Each collet has range of only few thousandths of an inch over or under size
stamped on collet

|
Collet Chuck
Special adapter fitted into taper of headstock spindle, and hollow draw bar having internal
thread inserted in opposite end of headstock spindle. It draws collet into tapered adapter
causing collet to tighten on workpiece.

46-46
Types of Lathe Dogs
 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 drive plate
– Used in precision turning

Types of Lathe Dogs
 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

Left-Hand Offset Toolholder
 Offset to the right
 Designed for machining work close to chuck or faceplate and cutting right to
left
 Designated by letter L

Right-Hand Offset Toolholder
 Offset to the left
 Designed for machining work close to the tailstock and cutting left to right
 Also for facing operations
 Designated by letter R

Straight Toolholder
 General-purpose type
 Used for taking cuts in either direction and for general machining operations
 Designated by letter S

Straight Tool holder
 General-purpose type
 Used for taking cuts in either direction and for general machining operations
 Designated by letter S

03 Drilling-Working principles, types, specifications
53
Working Principles
Drilling is an operation of making a circular hole by removing a volume of metal
from the job by cutting tool called drill.
A drill is a rotary end-cutting tool with one or more cutting lips and usually one or
more flutes for the passage of chips and the admission of cutting fluid.
A drilling machine is a machine tool designed for drilling holes in metals.
Besides drilling round holes, many other operations can also be performed on the
drilling machine such as counter- boring, countersinking, honing, reaming, lapping,
sanding etc.

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Constructional/Principal Parts
This machine consists of following parts
1. Base
2. Pillar
3. Main drive
4. Drill spindle
5. Feed handle
6. Work table

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TYPES
(1) Portable drilling machine
(2) Sensitive drilling machine
(a) Bench mounting
(b) Floor mounting
(3) Upright drilling machine
(a) Round column section
(b) Box column section machine
(4) Radial drilling machine
(a) Plain
(b) Semiuniversal
(c) Universal
Drilling machines are classified on the basis of their constructional features, or
the type of work they can handle. The various types of drilling machines are:
(5) Gang drilling machine
(6) Multiple spindle drilling machine
(7) Automatic drilling machine
(8) Deep hole drilling machine
(a) Vertical
(b) Horizontal

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TYPES
(1) Portable drilling machine
•Small compact unit and used for drilling holes in work pieces in any position, which cannot be
drilled in a standard drilling machine.
•Portable drilling machines are fitted with small electric motors (both A.C. And D.C. Power supply).
•Operate at fairly high speeds and accommodate drills up to 12 mm in diameter.
(2) Sensitive drilling machine
•workpiece is mounted on the table and drill is fed into the work by purely hand control.
•operator senses the drilling action in the work piece, at any instant, it is called sensitive drilling
machine.
•Drills of diameter from 1.5 to 15.5 mm.
Depending on the mounting of base of the machine
(a) Bench mounting
(b) Floor mounting

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TYPES
(3) Upright drilling machine
•Larger and heavier than a sensitive drilling machine.
•Handling medium sized workpiece and is supplied with power feed arrangement.
•Ranging up to 75 mm diameter drills.
•Based on the construction
(a) Round column section
(b) Box column section machine

03 Drilling-Working principles, types,
specifications principal parts, accessories and
attachments.
58
TYPES
(4) Radial drilling machine
Construction: -
The radial drilling machine consists of a
heavy, round vertical column supporting a
horizontal arm that carries the drill head.
Arm can be raised or lowered on the column
and can also be swung around to any
position over the work and can be locked in
any position.
The table of radial drilling machine may also
be rotated through 360 deg.
The maximum size of hole that the machine
can drill is not more than 50 mm.

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TYPES
Depending on the different movements of horizontal arm, table and drill head, the
radial drilling machine may be classified into following types
(a) Plain
In a plain radial drilling machine, provisions are made for following three movements
1. Vertical movement of the arm on the column,
2. Horizontal movement of the drill head along the arm, and
3. Circular movement of the arm in horizontal plane about the vertical column.
(a) Semiuniversal
In a semi universal drilling machine, in addition to the above three movements, the
drill head can be swung about a horizontal axis perpendicular to the arm.
(a) Universal
In universal machine, an additional rotatory movement of the arm holding the drill
head on a horizontal axis is also provided for enabling it to drill on a job at any angle.

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TYPES
(5) Gang drilling machine
A number of single spindle drilling machine columns are placed side by side on a
common base and have a common worktable.
A series of operation may be performed on the job by shifting the work from one
position to the other on the worktable.
This type of machine is mainly used for production work.
(6) Multiple spindle drilling machine
The multiple-spindle drilling machine is used to drill a number of holes in a job
simultaneously and to reproduce the same pattern of holes in a number of identical
pieces in a mass production work.
This machine has several spindles and all the spindles holding drills are fed into the work
simultaneously.
Feeding motion is usually obtained by raising the worktable.

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TYPES
(7) Automatic drilling machine
(8) Deep hole drilling machine
(a) Vertical
(b) Horizontal

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TYPES of Drills
A drill is a multi point cutting tool used
to produce or enlarge a hole in the
workpiece.
It usually consists of two cutting edges
set an angle with the axis. Broadly there
are three types of drills:
1. Flat drill,
The disadvantage of this type of drill is
that each time the drill is ground the
diameter is reduced.
2. Straight-fluted drill, and
3. Twist drill- most common type

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Number sizes
In metric system 0.2 to 100 mm
British system No. 1 to No. 80 diameter of drills increases in steps of
approximately by 0.002 inch.
Number 80
Number 1
largest diameter - 0.228 inch
smallest diameter 0.0135 inch
Number 1 – 60
Number61 - 80
standard sets of drills
are not so commonly used
Letter sizes from A to Z
drill sizes range
increasing in steps of approximately O.010 inch
fractional sizes
A - smallest
Z - largest
diameter - 0.234 inch
diameter - 0.413 inch

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SIZES OF A DRILLING MACHINE
The size of a portable drilling machine is decided by the maximum diameter
of the drill that it can hold.
To specify a drilling machine completely, following other parameters may also be
needed:
1. Table diameter
2. Number of spindle speeds and feeds available
3. Maximum spindle travel
4. Morse taper number of the drill spindle
5. Power input
6. Net weight of the machine
7. Floor space required, etc.

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A twist drill has three principal parts:
(i) Drill point or dead centre
(ii) Body
(iii) Shank.
Drill Material
•High speed steel.
•High speed steel is used for about 90 per cent of all twist drills.
•For metals more difficult to cut, HSS alloys of high cobalt series are used.

66
Fig: Geometry and nomenclature of twist drill

68
Drill axis is the longitudinal centre line.
Drill point is the sharpened end of the drill body consisting of all that part which is shaped to produce lips, faces and chisel edge.
Lip or cutting edge is the edge formed by the intersection of the flank and face Lip length is the minimum distance between the outer corner and the
chisel-edge corner of the lip.
Face is that portion of the flute surface adjacent to the lip on which the chip impinges as it is cut from the work.
Chisel edge is the edge formed by the intersection of the flanks.
Flank is that surface on a drill point which extends behind the lip to the following flute.
Flutes are the grooves in the body of the drill, which provide lips, allow the removal of chips, and permit cutting fluid to reach the lips.
Flute length is the axial length from the extreme end of the point to the termination of the flutes at the shank end of the body.
Body is that portion of the drill nomenclature, which extends from the extreme cutting end to the beginning of the shank.
Shank is that portion of the drill by which it is held and driven,
Heel is the edge formed by the intersection of the flute surface and the body clearance.
Body clearance is that portion of the body surface reduced in diameter to provide diametric clearance.
Core or web is the central portion of the drill situated between the roots of the flutes and extending from the point end towards the shank; the point end of
the core forms the chisel edge.
Lands are the cylindrically ground surfaces on the leading edges of the drill flutes. The width of the land is measured at right angles to the flute.
Recess is the portion of the drill body between the flutes and the shank provided so as to facilitate the grinding of the body. Parallel shank drills of small
diameter are not usually provided with a recess.
Outer corner is the corner formed by the intersection of the lip and the leading edge of the land.
Chisel edge comer is the corner formed by the intersection of a lip and the chisel edge.
Drill diameter is the measurement across the cylindrical lands at the outer corners of the drill. .
Lead of helix is the distance measured parallel to the drill axis between corresponding points on the leading edge of a flute in one complete turn of the
flute.
Helix angle is the angle between the leading edge of the land and the drill axis.
Rake angle is the angle between the face and a line parallel to the drill axis. It is bigger at the face edges and decreases towards the centre of the drill to
nearly 0°. The result is that the formation of chips grows more un-favourable towards the centre.
Lip clearance angle is the angle formed by the flank and a plane at right angles to the drill axis; the angle is normally measured at the periphery of the drill.
To make sure that the main cutting edges can enter into the material, the clearance faces slope backwards in a curve. The clearance angle is measured at the face
edge, must amount to 5° up to 8°.
Point angle is the included angle of the cone formed by the lips.

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OPERATIONS PERFORMED ON DRILLING MACHINE
1. Drilling
2. Reaming
3. Boring
4. Counter boring
5. Countersinking
6. Spot facing
7. Tapping
8. Lapping
9. Grinding
10. Trepanning.

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Drilling -
Reaming - Operation of sizing and finishing a hole already made by a drill.
Reaming operation serves to make the hole smooth, straight and accurate in
diameter.
Boring - operation where enlarging a hole by means of adjustable cutting tools with
only one cutting edge is accomplished.

71
Counter-Boring - operation of enlarging the end of a hole cylindrically,
as for the recess for a counter-sunk rivet.
Counter-Sinking - operation of making a cone shaped enlargement of the end of a
hole, as for the recess for a flat head screw.

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Lapping – operation of sizing and finishing a hole by removing very small amounts
of material by means of an abrasive.
Tapping - operation of cutting internal threads by using a tool called a tap.
Core drilling – main operation, which is performed on radial drilling machine for
producing a circular hole, which is deep in the solid metal by means of revolving tool
called drill.

04 Boring Machine-Working principles, types, specifications
principal parts, accessories and attachments Various
operations, boring tools and bars, boring heads
75
Boring - operation where enlarging a hole by means of adjustable cutting tools with
only one cutting edge is accomplished.
Working Principles

76
Boring Tools
Boring is cutting a hole in wood with a tool called a bit.
Holes of 6 mm size or larger are bored.
Holes of 6 mm size or smaller are drilled.
Commonly used boring tools bits for wood.
1. The center bit
2. Auger bits
3. Countersink bits
4. Shell and spoon bit
5. Expanding bits
6. Forstner bits
7. Snail bits
8. Rose bits
9. Bradawl
Boring Tools
1. Hand operated drills
2. Machine operated drills
3. Twist drill 4. Countersunk
5. Brace 6. Auger bit
7. Bit gauge

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Boring Machine Types
•The boring machine is one of the versalile machine tool used to enlarge already
drilled hole.
•Boring operation can be performed on lathe as that of turning where tool is stationary
and work piece is rotating.
•But in case of boring is rotating and work piece is stationary which is similar to
•Drilling ,reaming , milling etc.
Boring machines
1. Horizontal Boring Machine (HBM)
2. Vertical Boring Machine (VBM)
3. Precision (Jig) Boring Machine (PBM)

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The work is supported on a table which is stationary and tool revolves in a horizontal
axis.
•Can perform boring, reaming, turning, threading, facing, milling , grooving and
many other operations with suitable tools.
•Work piece which are heavier and asymmetrical can be easily held and machined.
•Different types has been designed to suit the different purpose.

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Block diagram of horizontal boring machine

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(1) Head Stock
•It is the most important part of a boring machine.
•It contains spindles.
•It supports, drives and feeds the boring tool.
•The spindle rotation is reversible for backing out tools.
•Boring tool is held in boring head which will be held in head stock.
(2) Column
•Column supports head stock and tail stock.
It guides up and down movement by means of ways.
•It is hollow and heavily constructed.
•To balance head stock and make it easy to move.
•Columns are keyed, dowelled and bolted to the base of the machine.

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(3) Runways
•Definition : When ever the column is traversing the base used is known as runway.
•Main function of runways are to carry the main column, end support column and
rotary table if any.
(4) End Support Column
•Definition : An out-board bearing is required to support the other end of the bar is
known as end END SUPPORT COLUMN.
•End support column is necessary in case of long boring and heavy tools are used.
•There is an opened and closed type of end support.

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(5) Table
•Main function of the table is to support for holding the workpiece rigidly during the
operation.
•Table is equipped with suitable ranges of feeds as well as quick reverse mechanism.
•Table moves perpendicular to the axis of the spindle.
(6) Saddle
•The main function of saddle is to provide a compound movement of the table.
•This helps the table to move axially as well as transversely to the spindle.
Applications Of HBM
1.Horizontal boring machine can be used to drill, bore ream holes.
2.These are widely used in batch production where work piece is less.
3.These machine can also be used for machining type parts like gear boxes and engine
blocks.

85
•The work rotates on a horizontal table about a vertical axis and the tool is stationary
except for feed.
•Machine may look like a vertical lathe.
•Larger diameter and heavy work pieces, can be set up more quickly than in lathe.
•Multiple tooling may be adapted with its turret type tool post, increasing the rate of
production.

88

89

90
It uses a single point cutting tools to machine surfaces rapidly and accurately.
•Cemented carbide and diamond tipped tools are operated at a very high cutting speed
to produce accurately sized holes with fine surface.
•Jig boring machine is a precision boring machine, resembles to vertical milling
machine in construction.
•Accurate positioning of holes is achieved by Lead screw method or Mechanical /
Electrical Gauging method or Optical measuring method.
•Jig-Boring Machine a metal-cutting machine for finishing holes, planes, and slots
with a highly precise location of centers or surfaces without the use of special
attachments for tool alignment. operated by highly skilled workers.

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•Jig-boring machines are used for boring, drilling, counter-sinking, reaming, milling, and
other types of finishing in individual and small-scale production during the manufacture of
cutting and measuring tools, jigs, dies, and key components of machines and instruments.
Devices with stable and adjustable end gauges and indicator sensing units are used on
jig-boring machines for precise measurements; also used are lead screws with dials and
a vernier, which are equipped with error-elimination compensators, and graduated shafts
with optical measuring instruments.
•There are two types of these machine tools: double-sided (gantry) machines with a one-
movement table and open-sided (single-sided, overhanging) machines with a two-
movement table. In open-sided machines the spindle head moves only vertically; in the
double-sided machines it moves horizon-tally along the crosspiece, which can travel in a
vertical direction. machines are operated by highly skilled workers.

92
•The manufactured article and the cutting tool on the jig-boring machine are moved
relative to one another along orthogonal coordinates (with linear displacement
accuracy to 2 microns) and polar coordinates (with angular displacement accuracy
to 5 seconds of arc). Sturdy construction is a feature of jig-boring machines, which
have smooth drive motions and accurate balancing of fast-rotating parts (to reduce
vibration).
•The machines are installed in insulated areas in which a constant temperature of
20°C is maintained. Jig-boring machines are operated by highly skilled workers.

BORING HEAD OR CUTTER HEAD Boring Bar

BORING HEAD OR CUTTER HEAD
 Boring heads are used for mounting cutters while machining large diameter holes where
a standard boring bar is unsuitable due to smaller diameter or overhanging of cutter.
 Two or more cutters held on boring head
 boring head supports tool & reduce machine time due to larger numbers of cutting
edges.
 Boring heads are used for mounting cutters while machining large diameter holes where
a standard boring bar is unsuitable due to smaller diameter or overhanging of cutter.
 Two or more cutters held on boring head
 boring head supports tool & reduce machine time due to larger numbers of cutting
edges.

96
Ansar Allauddin Mulla
ansarmulla212@gmail.com

Manufacturing Processes

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