drilling machine & reamers

8/10/2019 Drilling Machine & Reamers

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DRILLING M CHINE


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The primary function of a drilling machine is to originate a hole. But it can

be used to perform various types of similar type of operations. In a drilling

machine a hole can be drilled quickly at low cost. This hole is generated by the

rotating edge of a cutting tool known as drill. This drill or drill bit exerts large

amount of force on the job. So as this machine exerts vertical pressure to originate

a hole, this machine is sometimes loosely called as DrillPress.


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TYPES OF DRILLING MACHINE

1. Portable Drilling machine 5. Gang Drilling machine

2. Sensitive Drilling

machine

a) Bench Mounting 6. Multiple Spindle Drilling machine

b) Floor Mounting 7. Automatic Drilling machine

3. Upright Drilling

machine

a) Box Column8. Deep-hole Drilling

machine

a) Vertical

b) Round Column b) Horizontal

4. Radial Drilling machine

a) Plain

b) Semi Universal

c) Universal


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1. PORTABLE DRILLING MACHINE:Small size (12 to 18 mm) holes

are drilled on jobs at any position, which are difficult to drill by

other type of machines. Not only A.C. or D.C. but pneumatic or

hydraulic power is also available

2. SENSITIVE DRILLING MACHINE: Small size machines

designed for drilling small size holes on light work. Automatic

feed is not available in this type of machines. High rotational

speed is required as the diameter of the drill is small. The drill

size of this type of machine is ranges from 15 to 15 mm. This

machine can be directly mounted on the floor or can be

mounted on a table depending on the type of operation.


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3. UPRIGHT DRILLING MACHINE: This machine is comparatively

heavier in construction to drill medium size of holes. The fig shows

round column type upright drill machine. It consists of a base on

which a vertical column is fixed. At the upper end of the column,

drill head is placed. Height of the drill head can be adjusted,

according to the size of the work. Drill spindle is rotated by a motor

attached with the drill head. A table is also there to accommodate

the job with suitable fixing device. Automatic feeding may available

in this type of machine. Up to 50mm. size of hole can be drilled by

this type of machine.


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3. UPRIGHT DRILLING MACHINE:


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4. RADIALDRILLINGMACHINE:The construction of this type of machine is heavier than

upright drilling machine and also used to drill medium to large size on large work pieces.

The machine has a heavy round vertical column on a large base. Radial arm of the machine

is supported on this column. This arm can be moved vertically up and down either by hand

or with the help of an electric motor to accommodate different size of job. It can also swivel

around the column to drill hole at any position of the work table.

The drill head contains rotating and feeding

mechanism (automatic also) of the drill bit and is

placed on the horizontal arm. Mechanism for

changing the radius of the drill head from the

column is also there. All these movement of the

machine allows drilling numbers of holes at several

on a work without changing the position of the

work. The work may be mounted on the table or

directly on the machine base.


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4. RADIALDRILLINGMACHINE:

PLAIN:In a plain radial drill machine i) the radial arm can be moved vertically

up & down, ii) the radial arm can be swiveled about the axis of the column in a

horizontal plane and iii) the drill head can be moved along the radial arm.

SEMI UNIVEERSAL: In case of a semi universal radial drill machine in

addition to these three movements, the drill head can be swung about a horizontal

axis perpendicular to the arm. This fourth movement allows drilling holes at an

angle to the horizontal plane.

UNIVERSAL: In case of a universal drill machine in addition to the above four

movements, the arm can be swung about its own axis in the horizontal plane. This

movement allows drilling holes in the vertical side of the work.


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5. GANG DRILLING MACHINE: This machine is basically production purpose machine.

Generally four or six spindles are mounted side by side in this machine. The distance

between the spindles may be fixed or adjustable type. The speed & feed of each spindle

can be controlled independently.


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6. MULTIPLE SPINDLES DRILLING MACHINE: This is also a production purpose machine.

Here all the spindles of the machine runs by a single motor and speed & feed cannot be

controlled independently but its position can be adjusted.


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7. AUTOMATIC DRILLING MACHINE: Automatic drilling machine is also a production purpose

machine where a series of machining operations like drilling, milling, tapping etc. are carried out

automatically. The work is shifted automatically from one station to another. So when the work is

loaded in the machine, drilling operation is carried out automatically.

8. DEEP-HOLE DRILLING MACHINE:This machine is

operated at high speed and low feed with sufficient

amount of lubricants. In some cases both the work as

well as the drill rotates. The machine spindle may be

horizontal or vertical type. The job may be supported at

3 or 4 positions. The drill is removed from the work each

time automatically after it penetrates into the work equalto the diameter of the drill. Generally rifle barrels, crank

shaft, long shafts etc. are used to produce by this type

of machine.


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SPECIFICATION OF A DRILL MACHINE

1. Size of the drill (Range) that can be drilled by the machine.

2. Diameter of the drill table.

3. Maximum spindle travel.

4. Number of feeds available.

5. Morse taper number of the drill spindle.

6. Power input required.

7. Floor space area required.

8. Approximate weight of the machine.

These are the most generalized specification. But sometimes less number specification specified a

particular type of machine. For example

Portable drill machine can be specified by the maximum diameter of the drill that can be rotatedby the machine.

Sensitive & Upright drill machines are specified by the diameter of the largest piece of the work

that can be centered under the drill spindle. i.e. the distance between the column and table

centre.

Radial drill machines are specified by the diameter of the column and the length of the radial arm.


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TOOL HOLDING DEVICES

1. BY DIRECTLY FITTING IN THE SPINDLE: Drill machine has a

spindle for holding the drill. It has a standard internal taper and thus

it can hold only one size of drill directly. Taper shank of the drill is

inserted inside the drill spindle and its tang is fitted inside the slot

provided for it and thus ensures a positive drive and reduces the

chances slipping. For removing from the spindle a drill drift is used.

2. BY USING A SLEEVE: Taper provided in the drill spindle and on

the shank of the drill is designated a number. Generally Morse Taper

number is used for this specification. Drill only the same Morse Tapernumber with the drill spindle can be fitted directly. But for drills

having Morse Taper number less than the spindle taper number is

fitted inside the spindle with the help of drill sleeve.

3. BY USING A SOCKET:If the taper number of the drill

is larger than the spindle taper number then a drillsocket is used. The fig shows the construction of a drill

socket. The upper part of the socket has an outside

taper which fits inside the drill spindle and that of at the

lower part has an internal taper for the drill..


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TOOL HOLDING DEVICES

4. BY USING CHUCKS: it is widely used for holding

small size drills of parallel shank. The jaws are

adjustable. Hence any size of drill between maximum and

minimum can be held in it. The drill chuck may be

tightened or loosened with the help of chuck key. A taper

arbor fitted at the arbor hole of the chuck and is placed

inside the taper hole of the spindle.

5. By special attachments

a) Tapping attachment; b) Floating attachment.


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DRILLING MACHINE OPERATIONS

1. Drilling; 4. Boring; 7. Spot facing;

2. Reaming; 5. Counter boring; 8. Trepanning;

3. Tapping; 6. Countersinking; 9. Grinding;

10. Lapping etc.


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1. DRILLING: It is the operation of producing a round hole on a solid job. In

drilling exactly round hole cannot be produced. It becomes slightly elliptical in

shape. Also in drilling exact size cannot be produced. Because of the axial load, itdeflects and thus always an oversize hole is produced. To make the hole exactly

circular and accurate in size, reaming is done. In drilling operation in drill, the toll

is placed in the rotating spindle and the job is fixed on the table of the machine.

Axial pressure is then applied so that the material removed in the form of chip.

2. REAMING: It is the operation of sizing and finishing a drilled hole. In this

operation a reamer is used in the machine instead of a drill. Reamer is a

multiple edge cutting tool and removed material in the form of very fine

particles like dust. Its metal removal capacity is very low and limited to 0375

mm. only.


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DRILLING MACHINE OPERATIONS3. TAPPING:It is the operation of producing internal thread in a drilled or reamed

hole. In this operation a tap is rotated by the machine while the job is held

stationary. For this operation three sets of taps are used. The first one is called

the Roughertap, and then the Intermediatetapis used and finally for finishing

Finishingtapis used.

For tapping in drilling machine, the tap is placed neither in the spindle directly nor with the help of a

drill chuck. It is placed in the spindle with the help of a Tapping Attachment.The tapping attachment

serves as a flexible connection between the drill spindle and the tap. The principle of working is that

when the tap reaches at the bottom or jams in the hole, the driving torque on the tap is released

immediately and thereby prevents any damage of the tap.

4. BORING: Boring is the operation of enlarging an existing hole. In this

process not only the diameter of the hole enlarged but also its position can

be changed, if required. By this process the hole become exactly round in

shape and surface quality is improved than a drilled hole. In this operation

the boring tool is fixed with the boring bar and is rotated by the spindle of the

machine while the job remains stationary on the table.



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5. COUNTER BORING:The operation of enlarging the end of a hole cylindrically

is called counter boring. A counter bore is used for this operation. The pilot

advances in the hole of the job and maintains alignment of the tool. The pilot is

interchangeable for different sizes of the hole. It is done for making the space for

the head of bolt or stud. The central box of leaf spring for vehicles has counter

bored hole for bolt head.

6. COUNTERSINKING: The cone shaped enlargement at the end of existing

hole is called countersinking. A countersink is used to make the top end of the

hole conical for the flat head screw. Thus the top of the head of screw is set

plain with the surface of the job. Standard angle of this operation is 60, 82 &

90 and the cutting speed for this operation is much less than drilling operation.

7. SPOT FACING:It is the process of producing flat Surface Square with the

existing hole. This is done for providing seat for the bolt-head or nut or

washer. Generally end milling cutter is used as the tool for spot facing and is

rotated while the job remain stationary on the table



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8. TREPANNING: It is the operation of producing large size of hole on

thin material. For this operation a centre hole is drilled first on the job.

Then the trepanning tool is placed at the drill spindle. The pilot of the

trepanning tool is placed inside the drilled hole so that the position of the

tool does not change. Now a block material is removed from the job as

shown in fig and thereby a large size of hole is produced.

9. GRINDING:Grinding operation may be performed in a drilling machine to finish a hardened hole.

The grinding wheel is made to revolve with the spindle and is fed up and down. A suitable grinding

wheel may be selected for surface grinding operation. Grinding can also be done to correct out of

roundness of the hole. The accuracy in grinding operation is quite high about 00025 mm.

10. LAPPING:Lapping is the operation of sizing and finishing a small diameter hole already hardened

by removing very small amount of material by using a lap. There are many kinds of lapping tools. The

copper head laps are commonly used. The lap fits in the hole and is moved up and down while it

revolves.

TAP SIZE DRILL


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TAP SIZE DRILL

WORK HOLDING DEVICES


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1. T-BOLT & CLAMP:There are so many types of clamps are used for

holding the job in a drilling machine. In most of the cases T-Bolts are

used with the clamp. T-Bolts are inserted in the T-Slots provided on the

machine table. A block of suitable size is placed at the rear end of the

clamp and then the nut is tightened for holding the job

2. DRILL PRESS VICE: Small regular shape (especially rectangular)

jobs are held in drill press vice for drilling operation. In this vice the job

is placed between the jaws of the vice and then the nut is tightened.

Suitable parallel plates can be used for holding the job in this vice if

required. The vice is also two types, namely PLANE type and

UNIVERSAL type.

Plane type vice is commonly used but here the top surface

of the job cannot be set at an angle with the horizontal which can be

done in case of a Universal vice



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3. STEP BLOCK:The fig shows the arrangement of a step block used in

drilling machine. Here T-Bolt is placed in the T-Slot provided on machine

table. A flat plate is used to hold the job and then the nut of the T-Bolt is

tightened. At the rear side step block is used so that the height of the flat

plate can be adjusted according to the height of the job.

4. V-BLOCK:It is an accurately machined block, top surface of which

has a V-Shape opening. It is used for holding and locating cylindrical

type of work. Sometimes half-round clamps are also used with this

block for holding the job more rigidly.

5. ANGLE PLATE: Angle plate has two faces right angle with each other.

Generally it is made from C.I. and the surfaces are accurately machined. One of

its faces is bolted on the table of the machine with the help of T-Bolts while the

job is fixed at the other face (i.e. the vertical face) with the help of suitable nuts

& bolts and clamps.



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6. DRILL JIGS:Drill jigs are used for mass production. The functions of

the jig are It holds the job rigidly on the machine table so that machining

can be done easily, it locates proper position of drilling so that marking is

not required and it guides the tool for accurate machining.

TYPES OF DRILL

1. Flat or Spade drill 2. Straight Fluted drill

3. Two-Lip Twist drill4. Taper Shank Core drill (3 or

4 fluted)

a) Parallel Shank (Short Series or "Jobbers" )

Twist drill

5. Oil Tube drill

b) Parallel Shank (Stub Series) Twist drill 6. Centre drill

c) Parallel Shank (Long Series) Twist drill

d) Taper Shank Twist drill


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TYPES OF DRILL

1. Flat or Spade drill: This is the simplest type of drill used for making hole in wood. Its cutting angle

varies from 90 to 120 while its relief angle or clearance angle ranges from 3 to 8. The

disadvantages of this type of drill are when ground for re-sharpening its diameter is reduced andduring machining its chip does not come out automatically.

2. Straight Fluted drill: This type of drill is used for soft materials like Brass, Aluminimum, Copper

etc. Here the flutes are parallel to the axis of the drill. The rake angle of this type of drill is 0 and there

is no lifting tendency of the job during machining.


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TYPES OF DRILL

3. Two-Lip Twist drill or Twist drill: This type of drills is produced by forging a straight fluted

drill and then twisting it. There after rough milling operation of the flute is done to make

approximate size of the drill and then heat treatment is carried out for hardening. Finally grinding

of the drill is done for accurate size and shape. Depending on the shape of the shank, twist drill

can be classified as StraightShank or Parallel Shank Twist Drilland TaperShank Twist Drill.

a) Parallel Shank (Short Series or "Jobbers") Twist drill: This type of drills is used for

fine work. It has two flutes and its diameter ranges from 02 to 16 mm. Rate of increase in

available diameter is 002 003mm in lower series and 025 mm in higher series.

b) Parallel Shank (Stub Series) Twist drill:Length of this type drills are small and used for

drilling shorter length. Helix angle of this type of drills are high. Its diameter ranges from 05

to 40 mm increasing 025 mm in lower series and 05 mm in higher series.

c) Parallel Shank (Long Series) Twist drill: Helix angle of this type of drill is comparatively

less and its diameter ranges from 15 to 16 mm. This type of drills is widely used in the

machine shop.


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TYPES OF DRILL

3. Two-Lip Twist drill or Twist drill: This type of drills is produced by forging a straight fluted drill and

then twisting it. There after rough milling operation of the flute is done to make approximate size of the

drill and then heat treatment is carried out for hardening. Finally grinding of the drill is done for

accurate size and shape. Depending on the shape of the shank, twist drill can be classified as

StraightShank or Parallel Shank Twist Drilland TaperShank Twist Drill.

d) Taper Shank Twist drill:Diameter of this type of drill ranges from 3 to 100 mm. This type of drill is

directly fits into the taper provided at the drill machine spindle with suitable drill sleeve or drill socket if

required. This type of drills is available in different Morse Taper number as, Morse Taper 1, Morse

Taper 2, Morse Taper 6 etc.


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TYPES OF DRILL

4. Taper Shank Core drill (3 or 4 fluted): This type of drill cannot originate a hole in solid materials but

used for enlarging purpose. The material is removed by the chamfered edge at the end of each flute.

Surface quality of this type of drill is batter with almost accurate size.

5. Oil Tube drill: This type of drill is used for producing deep holes. Inside the drill oil tube runs along

the length to carry oil directly at the cutting edges. Cutting fluid or compressed air is passes through

these tubes.

6. Centre drill: This is a two fluted straight shank twist drill

used to drill centers at the ends of a shaft, so that it can be held

between the centers of any machines.

DRILL SIZE


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DRILL SIZE

According to Metric SystemDiameter of Drill ranges from 02 to 100 mm in diameter.

According to British SystemDrills are designated by any one of the following three ways -

I. Number Size: In this system Drills are designated by a number ranging from 1 to

80. 80 be the smallest diameter equal to 00135and that of 1 be the largest diameter

equal to 0228. The increase in diameter is nearly equal to 0002.

II. Letter Size: In this system Drills are designated by the letter of alphabet ranging

from Ato Z. Abe the smallest diameter and is equal to 0234while Zis the largest

diameter and is equal to 0413. The rate of increment is 001.

III. Fraction System:This system is most commonly used. The diameter available in

this system ranges from 1/64to 5. The rate of increment of diameter from1/64to 1

3/4

is 1/64and then this increment also increases.

DRILL SIZE


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DRILL SIZE

According to Indian Standard systemDrills are designated or specified by the

following parameters

I. Type of the drill shank (With series if required)

II. Diameter of the drill in mm.

III. I.S. Number (IS:599 means Standard Drills)

IV. Material of the Drill (like H.S.S.; CS; etc.)

V. Job material (like NNormalMaterial, HHardMaterial, SSoftMaterial)

VI. Point Angle or Lip Angle of the Drill.

For example : Parallel Shank Twist Drill (Long) 2500 IS:599-HSS

S

118 means the drill is of parallel shank long series twist drill type having diameter

25mm and made from HSS. It will be used for drilling soft material and the point

angle or lip angle of the drill is 118.

ELEMENTS OF TWIST DRILL


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ELEMENTS OF TWIST DRILL

1. Flutes 2. Tang

3. Land 4. Body

5. Helix Angle or Rake Angle 6. Neck

7. Point Angle 8. Heel

9. Chisel Edge Angle 10. Lip Angle

11. Lip Clearance Angle 12. Face

13. Shank 14. Flank

MACHINING TIME


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CUTTING SPEED:The cutting speed in drilling operation refers to the peripheral speed of a point on

the surface of the drill in contact with the work. It is generally expressed in m/min.

i.e. cutting speed

. Where D is the diameter of the drill in mm. and N is the rotational speed in rpm.

Cutting speed depends on

a. The kind of material being drilled. Softer the material higher will be the cutting speed.

b. Cutting tool material.

c. Quality of the surface finish required.

d. Efficient use of cutting fluid.

e. Method of holding the work.

f. The size, type and rigidity of the machine.

MACHINING TIME

MACHINING TIME


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FEED:The feed of a drill is the distance through which the drill moved into the work at each revolution

of the machine spindle. It is generally expressed in mm. per revolution.

Where Sm= Feed per min.; Sr= Feed per revolution and N is the rpm.

The amount of feed depends on

a. Type of the material.

b. Rigidity of the job and machine.

c. Depth of the hole to be produced.

d. Type of finish required.

e. Power available.

f. Range of feed (in case of automatic machines) available.

DEPTH OF CUT:In case of drilling operation depth of cut is always half of the drill diameter. i.e. D/2.

MACHINING TIME

MACHINING TIME


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MACHINING TIME

L1

Thickness of the job.

L2Approch of the drill (029D) mm.

L3Overrun of the drill (029D) mm.

L4Allowance

.

L = (L1+ L2+ L3+ L4) mm.

Machining timemin.

TYPES OF REAMER


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TYPES OF REAMER

Reamer is a multi-edge cutting tool used for finishing (smoothing, sizing and

shaping) a hole produced by drilling or boring or casting etc.

Reamers are broadly classified as

1 Hand Reamers:

The reamers which are held and

used by hands called as hand reamers.

2 Machine Reamers:

The reamers which are directly used

in machines called as machine

reamers.

TYPES OF REAMER


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TYPES OF REAMER

According to IS Specification Reamers are classified as follows:-

1. Chucking reamer with parallel or taper

shank 4. Parallel hand reamer with parallel shank

(i) Fluted reamer

(ii) Rose Reamer 5. Parallel or taper shank socket head reamer

6. Shell reamer

2. Machine bridge reamer 7. Taper pin hand reamer or Machine reamer

3. Machine jig reamer 8. Expansion reamer

TYPES OF REAMER


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TYPES OF REAMER

1. Chucking reamer with parallel or taper shank (Fluted) : This type of reamer has short virtually

parallel cutting edges, with bevel lead. There is a long recess between shank and cutting edges. The

shank may be straight or taper. Diameter of the straight shank reamer varies from 15 to 32 mm.whereas for taper shank it varies from 5 to 32 varies from 15 to 32 mm. whereas for taper

shank it varies from 5 to 32 mm. It is usually used in drill press, turret lathe, screw cutting

machine etc. Material removal capacity of this type of reamer is comparatively less but

accurate size is produced. The cutting action takes place at the cutting edges.

Chucking Reamer (Rose Type): Here the cutting action takes place by beveled edges

(45angled). This is the basic difference between fluted reamer and rose reamer. The body

of this type of reamer is slightly tapered to avoid binding in the holes. Material removal

capacity of this type of reamer is comparatively high.

TYPES OF REAMER


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TYPES OF REAMER

2. Machine Bridge Reamer: This type of reamers are used with portable electric or pneumatic drilling

machines in ship buildings, structural works, plate works etc. The diameter of this type of reamervaries from 64 to 37 mm. Its flutes may be straight or helical and has a taper shank to drive.

TYPES OF REAMER


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TYPES OF REAMER

3. Machine Jig Reamer: Diameter of such reamer varies from 7 to 50mm. It has a guide length

between cutting edges and shank. In the machine jig, this guide length fits accurately for accurate

orientation or location of the reamer. It has helical flutes and bevel lead cutting edges of shorter

length.

4. Parallel Hand Reamer with Parallel Shank: The shank of this type of reamer is straight and has a

square shape tang for hand operation. Diameter of the shank is equal to the nominal diameter of the

reamer. The teeth may be straight or helical with bevel lead. The cutting edges has slight taper at the

end for easy starting of operation. Material removal capacity of this type of reamer is small and is

limited to 0005 to 0125 mm.

TYPES OF REAMER


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TYPES OF REAMER

5. Socket Head Reamer (for Morse Taper): This type of reamer has taper cutting edges to suit

Morse Taper. The flute may be straight or helical. The shank of the reamer may be straight or taper. It

can be operated by either hand or machine.

6. Shell Reamer: Large size holes are machined by shell reamers. It has a through axial hole to fit an

arbor or mandrel. Different sizes of shell reamers can fit on a single arbor. Diameter of shell reamer

varies from 34 to 100 mm.

TYPES OF REAMER


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TYPES OF REAMER

7. Taper Pin Reamer: This type of reamer is either hand driven or machine driven. The cutting edges

are tapered in 1 in 50, so that it can machine holes for taper pin.

8. Expansion Reamer: The fig. shows an expansion type reamer. Its nominal diameter can be

adjusted by loosing or tightening the taper plug nut. For this different size of holes (Within limit) can be

finished by this type of reamer. Also the wear of the cutting edges can be adjusted accordingly.

CHART OF CUTTING SPEED IN DRILLING MACHINE (m/min.)


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CHART OF CUTTING SPEED IN DRILLING MACHINE (m/min.)

MATERIAL HSS DRILL BIT CS DRILL BIT

Soft Cast Iron 30 - 45 12 - 23

Medium Cast Iron 21 - 30 915

Malleable Iron 24 - 27 914

Mild Steel 24 - 45 917

Stainless Steel 18 - 21 75105

Aluminium and alloys 60 - 90 24

45

Brass and Bronze 60 - 90 24 - 45

Copper 18 - 30 75 - 15


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THANK YOU

drilling machine & reamers

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