Drilling and Broaching Machine Guide

By
R.ARUL
Assistant Professor
Mechanical Engineering Department
arulsivagiri.r@gmail.com
08-10-2021
1

Drilling machines — specifications, types - feed
mechanism, operations — drill tool nomenclature
—broaching —specifications, types, tool
nomenclature, broaching operations — grinding
— types of grinding machines — grinding wheels,
specifications — bonds —mounting and
reconditioning of grinding wheels.

» Drilling Machines
08-10-2021
3

 Introduction
 Working Principle
 Construction
 Specification For Portable Drilling
Machine
 Types Of Drilling Machine
 Operation Of Drilling Machine

 The drilling machine or drill press
is one of the most common and
useful machine employed in
industry for producing forming
and finishing holes in a work
piece. The unit essentially consists
of:
 1. A spindle which turns the tool
(called drill) which can be
advanced in the work piece either
automatically or by hand.
 2. A work table which holds the
work piece rigidly in position.

 The rotating edge of the drill
exerts a large force on the work
piece and the hole is generated.
The removal of metal in a drilling
operation is by shearing and
extrusion.
 Use:- Drilling machine is used to
drill blind and through holes in
work pieces.

 The machine has only a hand feed
mechanism for feeding the tool into
the work piece.
 This enables the operator to feel how
the drill is cutting and accordingly he
can control the down feed pressure.
 Sensitive drill presses are
bench or floor
manufactured
models, i.e.,
in
the base of machine
may be mounted on a bench or floor.
 The main
sensitive
operating
machine/drill
parts of a
press are
Base, Column, Table, and Drill Head.

 Bench Drilling Machine :- The simplest
type of sensitive drilling machine is
shown in figure. This is used for light
duty drilling work. This machine is
capable to drill hole up to 12.5mm
diameter
1. Motor :- An electric motor supplies the
required driving force to stepped pulley.
2. Base :- Base is the bottom part of
machine in which the column is fitted
upright.
3. Feed handle :- Handle is provided to
feed the drill in to the work piece. A
rake and pinion mechanism is provided
to drive the chuck.

 4.Column:- Column is the main
cylindrical part of drill machine on which
the other components are mounted.
 5.Belt guard:- Belt guard is provided to
cover the belt and pulley drive
mechanism to minimize the hazard of
accident.
 6.Chuck:- Chuck is provided to hold the
drill of different sizes up to 6.5 mm. Drill
size of more than 6.5 mm are to be fitted
directly in the Morse taper of spindle
 7.Work Table:- Work pieces are mounted
and held in position by the table. This
table can be tilted for drilling at an angle.

DESCRIPTION SPECIFIED
CAPACITY
•Drilling Capacity in Steel of 60
Kg/mm²Tensile Strength
•Tapping Capacity in Steel of 60
Kg/mm² Tensile Strength
50 mm(min.)
50 mm(min.)
SPINDLE
•Spindle feed traverse
•Spindle Morse Taper
•Spindle Ovality
350 mm(min.)
MT5/MT 6
0.005(max.)
SPINDLE SPEED AND FEEDS
•Spindle Speeds (Range)( Approx.)
•Number of Speed steps
•Feed range (Approx.)
•Number of feed steps
16 – 800 RPM
15(min.)
0.05 - 0.5 mm/rev
6(min.)

TRAVERSES
•Vertical Travel of Arm (Min)
•Range of Swing of Arm
•Traverse of column in bed
2400mm(min.)
0-360 Deg.
1200mm(min.)
DISTANCES
•Swing Radius of drilling spindle 2250 mm( min)
1420 mm( Max.)
•Farthest Distance of Spindle end 2700mm( min)
from floor when horizontal
drilling
•Lowest Distance of Spindle end 300 mm ( max)
from floor when horizontal
drilling

 Portable Drilling Machine
 Sensitive or Bench Drill
Drilling Machine(Single
Drilling Machine(Turret
 Upright
Spindle)
 Upright
Type)
 Radial Drilling Machine
 Multiple Spindle Drilling Machine
 Deep Hole Drilling Machine
 Gang Drilling Machine
 Horizontal Drilling Machine
 Automatic Drilling Machine

 It is a very small, compact and self
contained unit carrying a small
electric motor inside it.
 It is very commonly used for
drilling holes in such components
that cannot be transported to the
shop due to their size or weight or
where lack of space does not
permit their transportation to the
bigger type of drilling machine.
 In such cases, the operation is
performed on the site by means
of the portable electric drill.

 This type of drilling machine is
used for very light work.
 Its construction is very simple and
so is the operation .
 It consists of as shown in fig. of a
cast iron having a fixed table over
it.

 This machine is very useful
because of its wider range of
action.
 Its principal use is in drilling holes
on such work is difficult to be
handled frequently.
 With the use of this machine, the
tool is moved to the desired
position instead of moving the
work to bring the latter in
position for drilling.

 It is nothing but a type of multiple
spindle drilling machine, in which
the spindles are arranged in a
row.
 These spindles may be driven
either separately or collectively.
 This machine is very useful when
the nature of work is such that a
number of operations like drilling,
reaming, counter boring and
tapping, etc. are to be performed
in succession on it.

• Drilling
• Reaming
• Boring
• Counter Boring
• Counter Sinking
• Spot Facing
• Tapping

 Drilling :- It is the main operation
done on this machine. It is the
operation of producing a circular
hole in a solid metal by means of
a revolving tool called drill.
 Boring :- It is an operation used
for enlarging a hole to bring it to
the required size and have a
better finish.
 Counter sinking :- It is the
operation used for enlarging the
end of a hole to give it a conical
shape for a short distance.

• Reaming :- It is the operation of
finishing a hole to bring it to
accurate size and have afine
surface finish . This operation is
performed by means of a multi
tooth tool called reamer.
• Counter boring :- This operation
is used for enlarging only a limited
portion of the hole is called
counter boring .
• Tapping:- It is the operation done
for forming internal threads by
means of the tool called tap.

Nomenclature of Twist Drill
Axis – It is the longitudinal center line of the drill running through
the centres of the tang and the chisel edge.
Body – It is the part of the drill from its extreme point to the
commencement of the neck, if present. Otherwise, it is the part
extending upto the commencement of the shank. Helical grooves are
cut on the body of the drill.
Shank – It is the part of the drill by which it is held and driven. It is
found just above the body of the drill. The shank may be straight or
taper. The shank of the drill can be fitted directly into the spindle or
by a tool holding device.
Tang – The flattened end of the taper shank is known as tang. It is
meant to fit into a slot in the spindle or socket. It ensures a positive
drive of the drill.

Neck – It is the part of the drill, which is diametrically undercut
between the body and the shank of the drill. The size of the drill is
marked on the neck.
Point – It is the sharpened end of the drill. It is shaped to produce
lips, faces, flanks and chisel edge.
Lip – It is the edge formed by the intersection of flank and face.
There are two lips and both of them should be of equal length. Both
lips should be at the same angle of inclination with the axis (59°).
Land – It is the cylindrically ground surface on the leading edges of
the drill flutes adjacent to the body clearance surface. The alignment
of the drill is maintained by the land. The hole is maintained straight
and to the right size.

Flutes – The grooves in the body of the drill are known as flutes.
Flutes form the cutting edges on the point. It allows the chips to
escape and make them curl. It permits the cutting fluid to reach the
cutting edges.
Angles
Chisel edge angle – The obtuse angle included between the chisel
edge and the lip as viewed from the end of the drill. It usually ranges
from 120° to 135°.
Helix angle or rake angle – The helix or rake angle is the angle
formed by the leading edge of the land with a plane having the axis
of the drill. If the flute is straight, parallel to the drill axis, then there
would be no rake. If the flute is right handed, then it is positive rake
and the rake is negative if it is left handed. The usual value of rake
angle is 30° or 45°.

Point angle – This is the angle included between the two lips
projected upon a plane parallel to the drill axis and parallel to the
two cutting lips. The usual point angle is 118°. When hard alloys are
drilled the value increases.
Lip clearance angle – 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. The lip clearance angle ranges from 12° to 15°.

» Broaching Machines
08-10-2021
27

• Broaching is a machining operation in which a tool
used is called as broach
having series of cutting teeth.
• In this operation broach is either Pulled or
Pushed with the help of broaching machine on
the workpiece surface.
• Parts that is produced by the broaching have good
surface finish and
dimensional accuracy.

08-10-2021
30
BROACHING TOOL NOMENCLATURE

• Broach consist of three sets of cutting
teeth.Theyare:
1. Roughing teeth
2. Semi finishing teeth
3. Finishing teeth

• When the broach is fed in a straight line, metal is cut
in several successive layer with the help of broach.
• The thickness of each layer is same and called as feed
per tooth and sum of the thickness of all the layers is
called as depth of cut.

• Mainly broaching machines which are used in the
industries are of following types:-
1. Horizontal Broaching Machine
2. Vertical PullType BroachingMachine
3. Continuous Broaching Machine
4. RotaryTable BroachingMachine
5. Surface BroachingMachine
6. Keyway BroachingMachine

• Horizontal Broaching Machines are capable of both internal
and external
surfaces.
• In operation either workpiece is kept stationery and broach is
fed past or broach is kept stationery and workpiece is fed
past.
• This machine has bed similar to the lathe machine.
• This machine range from 2 to 60 tones and stroke of 3m for
internal broaching machine and for external broaching
machine it ranges upto 100 tones and stroke of 9m.

• This type of machine are
available forboth
pull up and pull down type of
machine.
• This machine is only used
for internal broaching or
hole broaching.
• In this machine we can mount
more than
one broach.
• In the pull down type the
workpiece is mounted on
table and the broach is
lowered to pass its front pilot
through the workpiece.
• In the pull up type, the only
difference is that the ram is
provided at the top which
will carry the broach from
bottom to top.

• This machine are available both in horizontal and vertical
type.
• In this machine the broach remains stationery while
the workpiece moves continuously past.
• In this machine the workpiece are fed past on the
chain which is traveling continuously with the help
of sprockets on both the end.
• The chain has a series of fixtures which will hold the
workpiece.
• In this machine the workpiece is loaded on a side and
unloaded on the other side.

• This machine is also used as a
Continuous Broaching
Machine.
• In this machine a table is
provided which
continuously rotates about
a vertical axis.
• On this the fixtures are
mounted and broach is
held tightly on broach
holder.
• The shape of the broach is
same as of the
table.
• As the table rotates the
workpieces are
loaded, machined and
unloaded.

• In this machine either workpiece or broach moves
across each other.
• This machines are generally vertical and hydraulically
operated.
• This machine is an alternative to milling machine so
machine fixtures are also used to hold the workpiece.
• These machines are used for large quantities of
workpiece having flat surfaces.

• This machine is the simplest type of machine and it can
be used forgeneral purpose also.
• If multiple keyways or splines are to be cut the single
broach can beused with the workpiece and indexed
after each other.
• This machines method is the oldest methods of all.

• Broach has a longer life than other tools.
• Broach can perform roughing and finishing
operations.
• High skilled operator is not required.
• Interchangeable components can be
produced at fasterrate.

• In this process, all jobs need a fixture.
• Sharpening of broach is difficult and
expensive.
• With the help of broaching, it is difficult to
produce blind holes.
• Initial cost of broach and broaching machine is
very high.

• Broaching used for producing the variety of
shapes, internal and external, regular and
irregular profiles.
• The examples of components produced by
broaching are as follows:
1. Bearing caps
2. Bearing bodies
3. Cylinder blocks
4. Connecting rods
5. Gears andTurbine
6. Keyways
7. Splines

» Grinding Machines
08-10-2021
43

www.bookspar.com | Website for Students | VTU
NOTES | QUESTION PAPERS 44

Grinding
 Grinding is a surface finishing operation
where very thin layer of material is removed
in the form of dust particles.
 Thickness of material removed is in range of
0.25 to 0.50 mm.
 Tool used is a abrasive wheel.

Abrasives
 Abrasive is the material employed for
sharpening, grinding and polishing
operations.
 Natural abrasive – emery, corundum,
quartz, sandstone, diamond, etc.
 Artificial abrasive – carborundum,
aloxite, alundum, etc.

Applications of abrasives
 Corundum : is a natural mineral which consists
of aluminium oxide. Hardest natural substance
after diamond.
 Used for shaping, finishing and polishing other tools.
 Emery : natural abrasive consisting of
aluminium oxide and little amount of iron
oxide.
 Silicon carbide : synthetic abrasive harder than
aluminium oxide.
 Used to grind metals like iron, brass and soft bronze.
 Used in non metals like wood and leather industries.

 Zirconia aluminia : it is a mixture of
zirconium oxide and aluminium oxide.
 Used in casting and foundry industries.
 Cubic boron nitride : is made up of
boron nitride with a cubic crystalline
structure.
 Used for hard coating material.
 Diamond :

Bonding materials
 These are adhesives which holds the
abrasive grains together.
 Vitrified process :
 Silicate process :
 Elastic process :
 Rubber or vulcanite process :

Grinding machines
 Grinding machine is a power operated
machine tool where, the work piece is fed
against constantly rotating abrasive wheel
to remove thin layer of material from
work.

Principle of grinding machines
 Work piece is fed against the rotating abrasive
wheel.
 Due to action of rubbing or friction between the
abrasive particles and work piece material is
removed.

Classification of grinding
machine
 Bench grinding machine
 Surface grinding machine
 Cylindrical grinding machine
 Center less grinding machine
 Internal grinding machine
 Special purpose grinding machine

Surface grinding machine
 It is machine basically used to grind flat
surface.
 Job is mounted to a table which moves
longitudinally as well as in transverse
direction.
 Manual feed or power feed.
 Work piece can clamped in two ways
 Manual clamps.
 Magnetic chuck.

 Internal pump and piping arrangement for
coolant.
 Protective guard for safety.

 Base
 Column
 Table traverse
and vertical feed
hand wheel.
 Wheel guard
and protective
guard.

 Working
 Work piece is clamped to the table by
operating magnetic chuck.
 Required grade of grinding tool is fixed to
spindle.
 Grinding operation is carried out be
operating both table traverse wheel and
vertical feed hand wheel.

Cylindrical grinding machine
 It is a process of grinding curved surfaces.
 Surface may be straight or tapered.
 Work piece is mounted on two centers, one
is tailstock centre and the other is headstock
centre.
 Head stock center may or may not revolve.

Working principle

Centre less grinding
machine
 It is used to grind curved surface work piece
which are long and slender.
 Work piece rests on a work-rest blade and is
backed by a second wheel called as
regulating wheel.
 Grinding wheel pushes the work piece down
the work-rest blade against the regulating
wheel.

Cutting terminology
 Speed : it is the peripheral speed of the
work piece per unit time. (m/min)
 Feed : it is the distance travelled by the
tool during each revolution of the work
piece. (mm/revolution).
 Depth of cut : it is the perpendicular
distance measured from the original
surface to the machined surface of the
work piece. (mm)


Drilling and Broaching Machine Guide

Recommended

Recommended

More Related Content

What's hot

What's hot (20)

Similar to Drilling and Broaching Machine Guide

Similar to Drilling and Broaching Machine Guide (20)

Recently uploaded

Recently uploaded (20)

Drilling and Broaching Machine Guide