This document provides information about basic machine tools, including lathes, drilling machines, and milling machines. It describes the classification, parts, specifications, operations, and accessories of lathes. It also discusses the working principle, classification based on design and spindle position, major parts, cutters, and milling operations of milling machines. For drilling machines, it covers classification, specifications, parts, and common operations like drilling, reaming, and tapping.
2. 5.1 Lathe
Classification of lathes
• lathes can be classified as:
1. Speed lathe
(i) Wood working lathe
(ii) Metal spinning lathe
(iii) Metal turning lathe
(iv) Polishing lathe
(v) Tool room lathe
(vi) Turret lathe
(vii) Capstan lathe
(viii) Special purpose lathe
(ix) Automatic lathe.
2. Engine lathe
(i) Step cone pulley drive lathe
(ii) Geared lathe
(iii) Variable speed lathe
3. Bench lathe
3. Lathe specifications
• The size of a lathe is expressed or specified by the following
items and illustrated in Fig.
1. The height of the centre’s measured from the lathe bed.
2. The swing diameter over bed. This is the largest diameter of
work that will revolve without touching the bed and is twice the
height of the centre measured from the bed of the lathe.
3. The length between centre's. This is the maximum length of
work that can be mounted between the lathe centers.
4. The swing diameter over carriage. This is the largest diameter of
work that will revolve over the lathe saddle, and is always
less than the swing diameter over bed.
5. The maximum bar diameter. This is the maximum diameter of
bar stock that will pass through hole of the headstock spindle.
6. The length of bed. This indicates the approximate floor space
occupied by the lathe.
6. THE HEADSTOCK
• The headstock is secured permanently on the inner ways at
the left hand end of the lathe bed, and it provides mechanical
means of rotating the work at multiple speeds. It comprises
essential y a hollow spindle and mechanism for driving and
altering the spindle speed. All the parts are housed within the
headstock casting.
• The spindle of the headstock, illustrated in Fig. is made of
carbon or nickel-chrome steel.
7. TAILSTOCK OR LOOSE HEADSTOCK
• The tailstock is located on the inner ways at the right hand end of
the bed. This has two main uses: (1) it supports the other end of
the work when it is being machined between centre’s, and (2) it
holds a tool for performing operations such as drilling, reaming,
tapping, etc. To accommodate different lengths of work, the
body of the tailstock can be adjusted along the ways chiefly by
sliding it to the desired position where it can be clamped by bolts
and plates.
8. • CARRIAGE
The carriage of a lathe has several parts that serve to support, move and
control the cutting tool. It consists of the following parts: (1) saddle, (2)
cross-slide, (3) compound slide or compound rest, (4) tool post, and (5)
apron.
• Saddle: The saddle is an H-shaped casting that fits over the bed and
slides along the ways. It carries the cross slide and tool post.
• The cross-slide: The cross-slide comprises a casting, machined on the
underside for attachment to the saddle and carries locations on the upper
face for the tool post or
• Compound rest: The compound rest or compound slide is mounted on
the top of the cross-slide and has a circular base graduated in
degrees. It is used for obtaining angular cuts and short tapers as well
as convenient positioning of the tool to the work.
• The tool post: This is located on the top of the compound rest to hold the
tool and to enable it to be adjusted to a convenient working position. The
type and mounting of the tool post depends upon the class of work for
which it is to be used.
• The apron: the apron is fastened to the saddle and hangs over the front of
the bed. It contains gears, clutches and levers for operating the carriage
by hand and power feeds.
10. Accessories used on lathe.
 Standard Accessories
1. Complete electrical wiring system fitted inside the
headstock with switches in the proper position.
2. Driving plate with carriers
3. Reduction sleeve socket
4. Tool post
5. Dead centers
6. Set of service tools
7. Operator's manual
 Special Accessories
1. Three-jaw self-centering chuck
2. Four-jaw independent chuck (other chucks like :-
combination chuck, magnetic chuck, collect chuck,
drill chuck and air or hydraulic chuck)
3. Face plate with jaws
4. Face plate without jaws
5. Universal face plate
6. Self-clamping chuck
7. Collet chuck
8. Live centre
9. Steady rest
10. Follow rest
11. Roller steady rest
12. Longitudinal tripping device
13. Square tool post
14. Drill holder
15. Coolant system with chip tray and reservoir
16. Splash guard
17. Chuck guard
18. Machine lamp
19. Multi-start threading dial
20. Hydro copy turning attachment
21. Taper turning attachment
14. Operations performed on lathe
• The most common operations which can be
carried out on a lathe machine are:-
1) Facing,
2) Plain turning,
3) Step turning,
4) Taper turning,
5) Drilling,
6) Reaming,
7) Boring,
8) Undercutting,
9) Threading,
10) Knurling.
20. 5.2 Drilling
INTRODUCTION
The drilling machine is one of the most important machine tools in a workshop. It
was primarily designed to originate a hole but it can perform a number of similar
operations. The basic purpose of a drilling machine is to drill cylindrical holes in Work
pieces. (Metallic and non-metallic materials). The holes are cut out of the material with a
cutting tool, which is known as drill. The drill is fixed in a rotating spindle and can be fed
towards the work-piece which may be fixed to the table or to the base of the machine.
The speed of the spindle and the feed can be adjusted according to the Work-piece.
Classification OF DRILLING MACHINE
1. Hand drilling machine
2.Portable drilling machine
3. Vertical spindle Drilling machines can be classified as:-
a) Sensitive drilling machine
b) Upright or column drilling machine can be further classified as
i) Pillar drilling machine ii) Box column drilling machine
4. Radial drilling machine
5. Gang drilling machine
6. Multi-spindle drilling machine
7. Automatic drilling machine
8. Deep hole drilling machine
21. SPECIFICATION OF THE DRILLING MACHINE : -
A heavy duty drilling machine is specified by following parameters.
1) Drilling capacity,
2) Taper in spindle (Morse no.),
3) Distance between spindle and column (maximum and
minimum) in case of radial drilling machine,
4) Transverse of spindle,
5) Minimum distance between spindle and table,
6) Minimum distance between spindle and base plate,
7) Working surface of table (i.e., diameter),
8) Range of spindle speeds,
9) Range of power feed per revolution,
10) Motor speed, and
11) Motor power.
22. Major parts of bench drilling machine with block diagram
23. DRILLING OPERATIONS :-
Drilling machines are primarily designed for drilling operations. In
addition to drilling, the following operations are also performed on them.
1. Boring
2. Counter boring
3. Reaming
4. Countersinking
5. Tapping
6. Lapping
7. Polishing
8. Spot facing
A) Drilling operation:-
It is an operation of producing a
circular hole in a work piece by
forcing a drill against it.
24. B) Reaming operation:-
It is an operation of slightly enlarging a machined hole to proper size with a
smooth finish. The reamer is an accurate tool and is not designed to remove much
metal. The reaming allowance is usually 0.2 mm only.
NOMENCLATURE OF THE DRILLING TOOL (DRILL)
25. 5.3 Milling
WORKING PRINCIPLE
Milling is a basic machining process by which a surface is generated by
progressive chip removal. The work-piece is fed into a rotating cutting tool. Sometimes the
work-piece remains stationary, and the cutter is fed to the work.
 A multiple-tooth cutter is used so that the material removal rate (MRR) is high.
 The desired surface is obtained in a single pass of the cutter or work.
 because very good surface finish can be obtained, milling is particularly well suited and
widely used for mass-production work.
 Many types of milling machines are used, ranging from relatively simple and versatile
machines that are used for general-purpose machining in job shops and tool and die work
(these are NC or CNC machines) to highly specialized machines for mass production.
Unquestionably, more flat surfaces are produced by milling than by any other machining
process.
Principle of a milling machine Some shapes produced on a milling machine
26. • Classification of Milling machine:-
Milling machines are classified in a variety of ways.
A) According to the drive
i) Cone-pulley belt drive
ii) Individual motor drive
B) According to design
i) Column & knee-type milling machine
ii) Planer milling machine
iii) Fixed bed-type milling machine
iv) Special milling machines, such as rotary table, duplicating & profiling.
c) Depending upon the position of the spindle
i) Horizontal spindle milling machines
ii) Vertical spindle milling machines.
27. Major parts of column & knee type universal milling machine
One of the features of the knee-and-column milling machine that makes it so
versatile is its capability for worktable feed movement in any of the x–y–z axes. The
worktable can be moved in the x-direction, the saddle can be moved in the y direction
and the knee can be moved vertically to achieve the z-movement. The special knee-
and-column machine is shown here i.e. The universal milling machine, which has a
table that can be swiveled in a horizontal plane (about a vertical axis) to any specified
angle. This facilitates the cutting of angular shapes and helixes on work parts.
It consists of following principle parts :- a) Column b) Knee c) Table d) Spindle
e) Over arm
28. Standard milling cutters :-
Milling cutters are made in various forms to perform certain classes of work,
and they may be classified as:
(1) Plain milling cutters,
(2) Side milling cutters,
(3) Face milling cutter,
(4) Angle milling cutters,
(5) End milling cutter,
(6) Fly cutter,
(7) T-slot milling cutter,
(8) Formed cutters,
(9) Metal slitting saw,
Milling cutters may have teeth on the periphery or ends only, or on
both the periphery and ends. Peripheral teeth may be straight or parallel to
the cutter axis, or they may be helical, sometimes referred as spiral teeth.
30. Milling operations
A) Face Milling:-
In face milling, the axis of the cutter is perpendicular to the surface being milled and
machining is performed by cutting edges on both the end and outside periphery of
the cutter.
31. B) Gang milling :-
It is a method of milling by means of two or more cutters
simultaneously having same or different diameters mounted on
the arbor of the milling machine.
32. C) Key-way milling :-
Fig. illustrates keyway milling operation. It is the operation of
making the semi cylindrical key ways for shafts.
33. D) End milling :-
End milling, in which the cutter diameter is less than the work
width, so as lot is cut into the part. It is a method of milling slots,
flat surfaces and profiles by end mills.