The document discusses drilling machines and drilling operations. It describes the main components and functions of drilling machines like bench drilling machines and radial drilling machines. It explains drilling tool components like drill bits and twist drills. It also covers other drilling operations like reaming, boring, counterboring, countersinking, spot facing and tapping that can be done on drilling machines. Safety precautions for operating drilling machines are also mentioned.

1. Drilling machine

2. Introduction
• Drilling is a metal cutting process carried out
by a rotating cutting tool to make circular
holes in solid materials.
• Tool which makes hole is called as drill bit or
twist drill.

3. Drilling
• Drilling is the operation of producing circular hole in the
work-piece by using a rotating cutter called DRILL.
• The machine used for drilling is called drilling machine.
• The drilling operation can also be accomplished in lathe, in
which the drill is held in tailstock and the work is held by
the chuck.
• The most common drill used is the twist drill.

4. Tool Nomenclature

5. Drill Bit
• A drill bit is a multi-point tool and typically
has a pointed end. A twist drill is the most
common type used

6. Drill Bit
• The twist drill or drill bit is made from High
Speed Steel, tempered to give maximum
hardness throughout the parallel cutting
portion.
• Flutes are incorporated to carry away the
chips of metal and the outside surface is
relieved to produce a cutting edge along the
leading side of each flute.

7. Twist drill
• Twist drills are available with parallel shanks up to
16mm diameter and with taper shanks up to 100mm
diameter and are made from high-speed steel.
• Standard lengths are known as jobber-series twist
drills, short drills are known as stub series, and long
drills as long series and extra long series.
• Different helix angles are available for drilling a
range of materials

8. Drill Bit
Fit in chuck
Fit direct into spindle

9. Drill Bit Features

10. Drill Bit Features
• The point of the drill is
ground to an angle of
118 degrees
• each side is ground
back to give " relief " of
about 12 degrees to
each cutting edge as
shown

11. The nomenclature of the twist drill is shown

12. Twist drills - Helix Types
• The helix angle of the twist drill is the
equivalent of the rake angle on other cutting
tools and is established during manufacture.
• The standard helix angle is 30 degrees, which,
together with a point angle of 118°, is suitable
for drilling steel and cast iron.

13. Helix types
Standard quick helix
slow

14. Helix types
• Drills with a helix angle of 20° — known as slow-helix
drills — are available with a point angle of 118° for
cutting brass and bronze and with a point angle of
90° for cutting plastics materials.
• Quick-helix drills, with a helix angle of 40° and a
point angle of 100°, are suitable for drilling the softer
materials such as aluminium alloys and copper

15. Drill Bit

16. Wood bits
masonry
steel

17. Subland drills
• Combination drills known as Subland drills combine a
number of operations in a single tool; for example …
• drill and ream,
• drill two diameters,
• drill and chamfer,
• drill and spotface,
• drill and counterbore,
• Each cutting edge has a separate land and flute, fig.
which enables cutting to take place and resharpening
to be easily carried out.

18. Subland drill
Examples of Subland-drill applications

19. Drilling machine
• A power operated machine tool which holds
the drill in its spindle rotating at high speeds
and when actuated move linearly against the
work piece produces a hole.

20. Types of drilling machine.
• Portable drilling machine
• Bench drilling machine
• Radial drilling machine
• Pillar drilling machine
• Gang drilling machine
• Multiple drilling machine

21. Portable drilling machine

22. Bench drilling machine
• These are light duty machines used in small
workshops.
• Also called Sensitive drilling machines because
of its accurate and well balanced spindle.
• Holes of diameter 1 mm to 15 mm.

23. Bench drilling machine

24. parts
• Vertical main column
• Base
• Moving drill head
• Work table
• Electric motor
• Variable speed gear box
and spindle feed
mechanism.

25. working
• Work piece with the exact location marked on
it with the centre punch is clamped rigidly on
the work table.
• spindle axis and center punch indentation are
in same line.
• Machine is started and drill bit is lowered by
rotating feed handle.
• Drill bit touches the work and starts removing
material.

26. Bench drilling machine

27. Radial drilling machine
• These are heavy duty and versatile drilling
machine used to perform drilling operate on
large and heavy work piece.
• Holes up to 7.5 cm.

28. Radial drilling machine

29. Radial drilling machine

30. Radial drilling machine-Parts
• Heavy base
• Table
• Vertical column
• Radial arm
• Drill head
• Elevating screw
• Motor for Elevating
screw
• Motor for spindle

31. Radial drilling machine-Working
• Radial Drilling Machine:- These drilling
machines are used to drill large diameter holes,
multiple holes in one setting of the heavy and
large work pieces.

32. Radial drilling machine-Working
• This usually large drilling machine possesses a
radial arm which along with the drilling head
can swing and move vertically up and down .
The radial, vertical and swing movement of
the drilling head enables locating the drill
spindle at any point within a very large space
on workpiece and odd shaped jobs. There are
some more versatile radial drilling machines
where the drill spindle can be additionally
swivelled and / or tilted.

33. Drilling machine operation
• Reaming
• Boring
• Counter boring
• Counter sinking
• Spot facing
• Tapping

34. Operations in drilling machine

35. Reaming
• It is a process of smoothing the surface of
drilled holes with a tool.
• Tool is called as reamer.
• Initially a hole is drilled slightly smaller in size.
• Drill is replaced by reamer.
• Speed is reduced to half that of the drilling.

37. Reaming

38. Reaming
• A reamer enters the workpiece
axially and enlarges an existing hole
to the diameter of the tool.
• A reamer is a multi-point tool that
has many flutes, which may be
straight or in a helix.
• Reaming removes a minimal
amount of material and is often
performed after drilling to obtain
both a more accurate diameter and
a smoother internal finish.

39. Boring
• It is process carried on a
drilling machine to
increase the size of an
already drilled hole.
• Initially a hole is drilled
to the nearest size and
using a boring tool the
size of the hole is
increased.

40. Boring

41. Counter boring
• This process involves
increasing the size of a
hole at only one end.
• Cutting tool will have a
small cylindrical portion
called pilot.
• Cutting speed = two-
thirds of the drilling
speed for the same
hole.

42. Counter sinking
• This is an operation of
making the end of a
hole into a conical
shape.
• Cutting speed = half of
the cutting speed of
drilling for same hole.

43. Counter sinking

44. Countersinking
• A countersink tool enlarges the
top portion of an existing hole to
a cone-shaped opening.
• Countersinking is performed
after drilling to provide space for
the head of a fastener, such as a
screw, to sit flush with the
workpiece surface.
• Common included angles for a
countersink include 60, 82, 90,
100, 118, and 120 degrees.

46. Countersinking Bits

47. Countersinking
• Common included angles for a countersink include
…

48. Spot facing
• It is a finishing
operation to produce
flat round surface
usually around a drilled
hole, for proper seating
of bolt head or nut.
• It is done using a special
spot facing tool.

49. Spotfacing
• Spotfacing provides a seat or flat surface at the
entrance and surrounding area of a hole.
• This flat surface allows the bottom of a screw or bolt
to seat squarely with the material.
• Spotfacing is commonly done on castings where
irregular surfaces are found.
• Spotfacing may be performed on a drill press with a
counterbore of suitable size for the operation.
• A proper size pilot must be used whenever this is
done on the drill press.

50. Spotfacing
spotface
Making a sloped
surface flat
To seat a nut
Back
spotface

51. Spotting
• Where holes in two parts are required to line
up with each other, a technique known as
‘spotting’ is carried out. The top part is
marked out and drilled.
• The two parts are then carefully positioned
and clamped together.

53. Boring

54. Counter boring

55. Counterboring
• A counterbore tool enlarges
the top portion of an existing
hole to the diameter of the tool.
• Counterboring is often
performed after drilling to
provide space for the head of a
fastener, such as a bolt, to sit
flush with the workpiece
surface.
• The counterboring tool has a
pilot on the end to guide it
straight into the existing hole

56. Counterboring Bit

57. Tapping
• Process of cutting
internal threads with a
thread tool called as
tap.
• Tap is a fluted threaded
tool used for cutting
internal thread
• Cutting speed is very
slow.

58. taps

59. Trepanning
• Trepanning is an
operation of producing
large sized cylindrical
holes using a special
drilling tool

60. Trepanning tool
Drilling large
diameter holes

62. Trepanning Tools

63. Drilling Machine Vice
• The Machine Vice has
slots in the side of the
base of the vice which
enable the user to
screw the Machine Vice
to the Drilling Machine
table.

64. Direct Clamping
Clamping set

65. Drill Bit
• A drill bit is a multi-point tool and typically
has a pointed end. A twist drill is the most
common type used

66. Drill Bit
• The twist drill or drill bit is made from High
Speed Steel, tempered to give maximum
hardness throughout the parallel cutting
portion.
• Flutes are incorporated to carry away the
chips of metal and the outside surface is
relieved to produce a cutting edge along the
leading side of each flute.

67. Twist drill
• Twist drills are available with parallel shanks up to
16mm diameter and with taper shanks up to 100mm
diameter and are made from high-speed steel.
• Standard lengths are known as jobber-series twist
drills, short drills are known as stub series, and long
drills as long series and extra long series.
• Different helix angles are available for drilling a
range of materials

68. Drill Bit
Fit in chuck
Fit direct into spindle

69. Drill Bit Features

70. Drill Bit Features
• The point of the drill is
ground to an angle of
118 degrees
• each side is ground
back to give " relief " of
about 12 degrees to
each cutting edge as
shown

71. The nomenclature of the twist drill is shown

75. Twist drills - Helix Types
• The helix angle of the twist drill is the
equivalent of the rake angle on other cutting
tools and is established during manufacture.
• The standard helix angle is 30 degrees, which,
together with a point angle of 118°, is suitable
for drilling steel and cast iron.

76. Helix types
Standard quick helix
slow

77. Helix types
• Drills with a helix angle of 20° — known as slow-helix
drills — are available with a point angle of 118° for
cutting brass and bronze and with a point angle of
90° for cutting plastics materials.
• Quick-helix drills, with a helix angle of 40° and a
point angle of 100°, are suitable for drilling the softer
materials such as aluminium alloys and copper

78. Drill Bit

79. Wood bits
masonry
steel

80. Subland drills
• Combination drills known as Subland drills combine a
number of operations in a single tool; for example …
• drill and ream,
• drill two diameters,
• drill and chamfer,
• drill and spotface,
• drill and counterbore,
• Each cutting edge has a separate land and flute, fig.
which enables cutting to take place and resharpening
to be easily carried out.

81. Subland drill
Examples of Subland-drill applications

82. Tool Holding

83. Tool Holding parallel shank drill
• Drills and similar tools with
parallel shanks are held in a drill
chuck.
• By rotating the outer sleeve, the
jaws can be opened and closed.
• To ensure maximum grip, the
chuck should be tightened using
the correct size of chuck key. This
prevents the drill from spinning
during use and chewing up the
drill shank.
Drill bit is only gripped by the shank

84. The Drill Chuck
Chuck
Morse Taper
Chuck Key
Keyless
Chuck

85. Tool Holding
• The chuck is fitted with a Morse-taper shank which fits into a
corresponding Morse taper in the spindle.
• The size of Morse taper is identified from smallest to largest
by the numbers 1, 2, 3, 4, 5, and 6. The included angle of each
taper is different but is very small, being in the region of 3
degrees.
• If the two mating tapered surfaces are clean and in good
condition, this shallow taper is sufficient to provide a drive
between the two surfaces.
• At the end of the taper shank, two fiats are machined, leaving
a portion known as the tang. This tang fits in a slot on the
inside of the spindle and its main purpose is for the removal
of the shank.
• Drills are also available with Morse-taper shanks which fit
directly into the spindle without the need for a chuck.

86. Tool Holding
Holding taper shank drills

87. Tool Holding
• Where a cutting tool or chuck has a Morse taper
smaller than that of the spindle, the difference is
made up by using a sleeve.
• Morse Taper Sleeve
• For example, a drill with a No. 1 Morse-taper shank
to be fitted in a spindle with a No. 2 Morse taper
would require a 1—2 sleeve.

88. Morse Taper Sleeve

89. Drill Drift
• To remove a shank from the spindle, a taper key known as a drift is used.

90. Using the drill drift
• The drift is inserted through a slot in the spindle
Strike here
to remove
Most modern machines
have a built-in drift

91. Specification of a radial drilling
machine
1.Max.depth hole can be drilled in MM
2.Max drilling radius in mm
3. Min. drilling radius in mm
4.Vertical power movement of arm in MM
5.Horizantal power movement of drill head on
arm in MM
6.Drilling motor power in kw (1.5kw)
7.Spindle speed rang rpm (50-2800rpm)

92. Specification of a radial drilling
machine
• Spindle Power capacity
1.5 hp for drilling motor
and 0.5 hp for elevating
motor.
• The range of speed of
spindle eg: 50 to 2800
rpm.

93. Specification of a radial drilling
machine
• Length of arm on which
drill head can traverse.
eg: 600 mm.
• Vertical movement of
the arm eg: 500 mm.
• Angular swing of arm
eg: 360˚

94. Specification of a radial drilling
machine
• Range to which drill bit
can reach eg: 350 mm
to 900 mm.
• Drill depth eg: 32 mm
for steel.

95. Precautions for Drilling machine
• Lubrication is important to remove heat and
friction.
• Machines should be cleaned after use
• Chips should be removed using brush.
• T-slots, grooves, spindles sleeves, belts, pulley
should be cleaned.
• Machines should be lightly oiled to prevent
from rusting

96. Safety Precautions
• Do not support the work piece by hand – use work
holding device.
• Use brush to clean the chip
• No adjustments while the machine is operating
• Ensure for the cutting tools running straight before
starting the operation.
• Never place tools on the drilling table
• Avoid loose clothing and protect the eyes.
• Ease the feed if drill breaks inside the work piece.