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MANUFACTURING PROCESSES-1
(131903)
CH-3 DRILLING MACHINES
MEET PATEL
INTRODUCTION
 Most important m/c tools in workshop next to the lathe.
Primarily designed to originate a hole.
Also can ...
TYPES OF DRILLING MACHINE
1. Portable drilling machine
2. Sensitive drilling machine
a) Bench mounting
b) Flour mounting
3...
PORTABLE DRILLING MACHINE
 Operated with ease any where in in the workshop.
 Used for drilling holes in work piece in an...
SENSITIVE DRILLING MACHINE
 Designed for drilling a small holes at
high speed in light job.
 The base of the m/c may be ...
 Sensitive drilling machine are capable of rotating drills of diameter from 1.5 to 15.5
mm.
 Super sensitive drilling ma...
UPRIGHT DRILLING MACHINE  Construction similar to sensitive drilling m/c and
designed for medium sized w/p.
 This is lar...
UPRIGHT DRILLING MACHINES PARTS
1. Base
2. Column
3. Table
4. Head
5. Spindle and drill head assembly
6. Spindle drive and...
3. Table
 It is mounted on column and is provided with T slots for clamping the work
directly on its face.
 It may be ro...
5. Spindle and drill head assembly
 The spindle is vertical shaft which holds the drill.
 It receives its motion from th...
6. Spindle drive mechanism
 The spindle drive mechanism of a drilling machine incorporates an arrangement
for obtaining m...
Radial Drilling Machine
Designed for medium to large and heavy w/p.
 It consists of a heavy, round, vertical column moun...
Radial drilling machine parts
1. Base
2. Column
3. Radial arm
4. Drill head
5. Spindle speed and feed mechanism
1. Base
 ...
3. Radial arm
 It is mounted on column extends horizontally over the base.
 It is massive casting with its front vertica...
Types of Radial Drilling Machine
1. Plain radial drilling machine-
In it provisions are made for vertical adjustment of th...
Gang Drilling Machine
 When a number of single spindle drilling m/c columns are
placed side by side on a common base and ...
Multiple Spindle Drilling Machine
 The function is to drill number of hole in a piece of
work simultaneously and to repro...
Automatic Drilling Machine
 It can perform a series of machining operations at successive units
and transfer the work fro...
Deep Hole Drilling Machine
 Special machines and drill are required for drilling deep holes in rifle barrels, crank
shaft...
Drilling Machine Operations
1. Drilling
2. Reaming
3. Boring
4. Counterboring
5. Countersinking
6. Spot facing
7. Tapping
...
2. Reaming
 It is an accurate way of sizing and finishing a hole which
has been previously drilled.
 The speed of the sp...
4. Counterboring
 It is a cylindrical flat-bottomed hole that enlarges another coaxial
hole, or the tool used to create t...
5. Countersinking
 It is the operation of making a cone-shaped enlargement of the
end of hole to provide a recess for a f...
6. Spot facing
 It is the operation of smoothing the surface
around a hole for the seat for a nut or the
head of a screw....
7. Tapping
 It is the operation of cutting internal threads by means of
a cutting tool called a tap.
 A tap may be consi...
8. Lapping
 It is the operation of sizing and finishing a small diameter hole already hardened by
removing a very small a...
Types of the drill:
1. Flat or spade drill
2. Straight fluted drill
3. Two-lip twist drill
a. Parallel shank – short serie...
Nomenclature of Drill
Tang
Neck
 Flutes- The groove in the body of the drill which provides lip.
Its functions are:
- To form the cutting edges on the po...
Chisel edge- The edge formed by the intersection of the
flanks. Also called “dead centre”
Face- The portion of the flute...
 Chisel edge angle- The angle between the chisel edge and the lip as viewed from the end of the drill. The usual value
of...
Nomenclature of Reamer
 Axis- The longitudinal centre line of the reamer.
 Recess- That portion of the body which is
reduced in diameter below ...
Types of Reamer
1.Chucking Reamer with Parallel or Taper Shank
 It has short and parallel cutting edges.
It has a long b...
2. Chucking Reamer
In this type of reamer the beveled edges remove the material.
The cutting edges are chamfered at an a...
3.Machine Bridge Reamer
It has parallel cutting edges and the flutes may be straight or helical
It is used with portable...
4. Machine Jig Reamer
It has short and parallel cutting edges with bevel lead and a guide between the shank
and cutting e...
5. Parallel Hand Reamer with Parallel Shank
It has virtually parallel cutting edges with taper and bevel lead
The flutes...
6. Socket Reamer
 It has straight or taper shank
It is may be driven by hand or machine
The cutting edges having Morse ...
7. Shell Reamer
It may be mounted on a arbor by an axial hole provided in the center
It has virtually parallel cutting e...
8. Taper Pin Reamer
It is employed for finishing the hole suitable for pins having a taper of 1 in 50
It has taper cutti...
9. Expansion Reamer
It is made in such a way that it may be adjusted to compensate for wear of the
blades by very small a...
Tool-Holding Devices
Drill press spindle provides means of holding and driving cutting tool
End may be tapered or thread...
Chucks
Hold straight-shank drills
Mounted on drill press spindle
Taper
Threads
- Held in spindle by self-holding taper in ...
Types of Drill Chucks
Key-type
 Most common
 Three jaws move simultaneously
when outer sleeve turned
• Tighten with key
...
Drill Sleeves and Sockets
Drill Sleeves
 Used to adapt cutting
tool shank to machine
spindle if taper on tool is
smaller ...
Drill Drift
Used to remove tapered-shank drills or accessories from drill press spindle
Always place rounded edge up so ...
Using the drill drift
 The drift is inserted through a slot in the spindle
Strike here to remove
Work-Holding Devices
1. T-bolt and clamps
2. Drill Press vise
3. Step block
4. Drill Jigs
1. T- bolts and clamps
 Work di...
Finger clamp
3. Goose neck clamp
 Used for holding work of different height
 Clamps made by forging so enough strong to
withstand loa...
5. Step Blocks
 To hold the work step block is used in combination with T-bolts and clamps
 For different height of job,...
6. Drill jigs
 It is used to clamp and unclamp the components quickly in mass production
 It hold the job securely, loca...
Morse Taper
Key less Chuck
Chuck
Chuck Key
Alignment Tests on Pillar Type Drilling Machine
Before carrying out the alignment tests, the machine is properly levelled ...
3. Perpendicularity of drill head guide to the base plate.
The squareness (perpendicularity) of drill head guide to the ba...
5. Perpendicularity of spindle sleeve with base plate.
This test is performed in both the planes specified in test (3) and...
6. True running of spindle taper.
For this test, the test mandrel is placed in the tapered hole of spindle and a dial
indi...
7. Parallelism of the spindle axis with its vertical movement.
This test is performed into two planes (A) and (B) at right...
8. Squareness of clamping surface of table to its axis.
For performing this test, the dial indicator is mounted in the tap...
Cutting speed, V=
D = Drill diameter, mm
N = rotational speed of the drill, rpm
MRR =
Machining Time (Tm) =
x = Tool appro...
A hole of 30 mm diameter and 65 mm depth is to be drilled. The suggested feed is 1.3
mm per rev. and the cutting speed is ...
Spindle rpm= 744
Time= 0.0724 min
MRR= 68.2479* 104
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Drilling machine

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SUBJECT : MANUFACTURING PROCESS -1
TOPIC :- DRILLING MACHINE

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Drilling machine

  1. 1. MANUFACTURING PROCESSES-1 (131903) CH-3 DRILLING MACHINES MEET PATEL
  2. 2. INTRODUCTION  Most important m/c tools in workshop next to the lathe. Primarily designed to originate a hole. Also can perform a number of similar operations. Holes may be drilled quickly and at a low cost. Hole is generated by the rotating edge of a cutting tool known as the drill which exerts large force on the work clamped on the table.
  3. 3. TYPES OF DRILLING MACHINE 1. Portable drilling machine 2. Sensitive drilling machine a) Bench mounting b) Flour mounting 3. Upright drilling machine a) Round column section b) Box column section 4. Radial drilling machine a) Plain b) Semi universal c) Universal 5. Gang drilling machine 6. Multiple spindle drilling machine 7. Automatic drilling machine 8. Deep hole drilling machine a) Vertical b) Horizontal
  4. 4. PORTABLE DRILLING MACHINE  Operated with ease any where in in the workshop.  Used for drilling holes in work piece in any position which can not be drilled in a standard drilling machine.  Some of the portable m/c operated by hand power, but most of the m/cs are driven by individual motor.  Maximum size of the drill that it can accommodate is not more than 12 to 18 mm.  M/c operated at high speed as smaller drills are only used.  Some of the portable m/c are driven by pneumatic power.
  5. 5. SENSITIVE DRILLING MACHINE  Designed for drilling a small holes at high speed in light job.  The base of the m/c may be mounted on a bench or on the floor.  There is no arrangement for any automatic feed of the drill spindle, the drill is fed into the work by purely hand control.  High speed and hand feed is necessary for drilling small holes.  Hand feed permits the operator to feel or sense the progress of the drill into the work so that if the drill becomes worn out or jams on any account the pressure on the drill may be released immediately to prevent it from breaking.  As the operator senses the cutting action, at any instant, it is called SENSITIVE DRILLING MACHINE.
  6. 6.  Sensitive drilling machine are capable of rotating drills of diameter from 1.5 to 15.5 mm.  Super sensitive drilling machines are designed to drill holes as small as 0.35mm in diameter and the machine is rotated at a high speed of 20,000 r.p.m. or above.
  7. 7. UPRIGHT DRILLING MACHINE  Construction similar to sensitive drilling m/c and designed for medium sized w/p.  This is larger and heavier than sensitive drilling m/c.  Large no. of spindle speeds and feeds available for different types of work.  The arm and table may be moved up and down on the column for accommodating w/p of different height.  The arm and table may be moved in an arc up to 180° around the column and may clamped at any position. This permits setting of the work below the Spindle.  Table may be rotated 360° about its own centre independent of the arm for locating w/p under the spindle. There are two general classes of upright drilling machine: 1. Round column section or pillar drilling m/c 2. Box column section  Construction of the m/c being not very rigid and table supported on a horizontal arm, intended for Lighter work and maximum size of holes that the m/c can drill is not more than 50 mm Round column and more than 50mm in Box column.
  8. 8. UPRIGHT DRILLING MACHINES PARTS 1. Base 2. Column 3. Table 4. Head 5. Spindle and drill head assembly 6. Spindle drive and feed mechanism 1. Base  It is part of m/c on which vertical column is mounted.  In belt drive machine the countershaft consists of a fast and loose pulley and cone pulley is fitted to the base of the m/c.  The top of the base in round column type upright drilling m/c is accurately machined and has T-slots on it so that large w/p and work holding devices may be set up and bolted to it. 2. Column  It is the vertical member of the m/c which supports the table and the head containing all the driving mechanism.  It should be sufficiently rigid to take up the entire cutting pressure of the drill.  It may be made of box section or round section.  Box column is more rigid.
  9. 9. 3. Table  It is mounted on column and is provided with T slots for clamping the work directly on its face.  It may be round or rectangular in shape.  For centering work below the spindle, the table of a pillar drilling machine may have three types of adjustment: vertical adjustment : radial adjustment about column : circular adjustment about its own axis. 4. Head  It is mounted on the top of the column and houses the driving mechanism for the spindle.  In some m/c the drill head may be adjusted up or down for accommodating different heights of work in addition to the table adjustment.  In lighter m/c , the driving motor is mounted at the rear end of the head counterbalancing the weight of the drill spindle.
  10. 10. 5. Spindle and drill head assembly  The spindle is vertical shaft which holds the drill.  It receives its motion from the top shaft through bevel gears.  A long key way is cut on the spindle and bevel gears is connected to it by sliding key.  This construction is made allow the spindle to be connected with the top shaft irrespective of its position when the spindle is raised or lowered for feeding the drill into the work.  The spindle is rotates within a non rotating sleeve (quill).  Rack teeth is cut on the outer surface of the sleeve.  The sleeve may be moved up or down by rotating a pinion which meshes with the Rack and this movement is imparted to the spindle to give the required feed.  The lower end of the spindle is provided with Morse taper hole for accommodating Taper shank drill.  A slot is provided at the end of the taper hole for holding the tang of the drill to impart it a positive drive.
  11. 11. 6. Spindle drive mechanism  The spindle drive mechanism of a drilling machine incorporates an arrangement for obtaining multiple speed of the spindle similar to the lathe to suit various machining conditions. It may be obtained as follows: 1. By step cone pulley drive 2. By step cone pulley drive with one or more back gears 3. By gearing
  12. 12. Radial Drilling Machine Designed for medium to large and heavy w/p.  It consists of a heavy, round, vertical column mounted on a large base.  The column supports a radial arm which can raised and lowered to accommodate w/p of different height. The arm may be swung around to any position over the work bed. The drill head containing mechanism for rotating and feeding the drill is mounted on a radial arm and can be moved horizontally on the guide ways and clamped at any position.  These three movement in a radial drilling m/c when combined together permit the drill to be located at any desired point on a large w/p for drilling the hole.
  13. 13. Radial drilling machine parts 1. Base 2. Column 3. Radial arm 4. Drill head 5. Spindle speed and feed mechanism 1. Base  The base of a radial drilling machine is a large rectangular casting that is finished on its top to support a column on its one end and to hold work table on the other end.  In some machines t-slots are provided on the base for clamping work when it serves as a table.  In some machine 2 or more number of bases are provided, so when drilling is done on a job supported on any one of the bases, another job may be set up on the other for a continuous production. 2. Column  It is a cylindrical casting that is mounted vertically at one end of the base.  It supports the radial arm which may slide up or down on its face.  An electric motor is mounted on the top of the column which imparts vertical adjustment of the arm by rotating a screw passing through a nut attached to the arm.
  14. 14. 3. Radial arm  It is mounted on column extends horizontally over the base.  It is massive casting with its front vertical face accurately machined to provide guide ways on which the drill head may be slide.  The arm may be swung round the column and some m/c its movement is controlled by a separate motor. 4. Drill head  It is mounted on radial arm and drives the spindle.  It encloses all the mechanism for driving the drill at multiple speed and at different feed.  All the mechanism and controls are housed within a small drill head which may be made to slide on the guide ways of the arm for adjusting the position of the drill spindle with respect to the work.  After the spindle has been properly adjusted in position the drill head is clamped on the radial arm. 5. Spindle drive and feed mechanism  There are two common methods of driving the spindle 1. A constant speed motor is mounted at the extreme end of the radial arm which balance partially the weight of the overhanging arm. 2. The motors drives a horizontal spindle which runs along the length of the arm and the motion is transmitted to the drill head through bevel gears. By train of gearing within the drill head, the speed of the spindle may be varied. Through another train of gearing within the drill head, different feeds of the spindle are obtained.
  15. 15. Types of Radial Drilling Machine 1. Plain radial drilling machine- In it provisions are made for vertical adjustment of the arm, horizontal movement of the drill head along the arm, and circular movement of the arm in horizontal plane about the vertical column. 2. Semi universal machine- In semi universal machine, in addition to the above three movement, the drill head can ne swung about a horizontal axis perpendicular to the arm. This fourth movement of the drill head permits drilling hole at an angle to the horizontal other than the normal position. 3. Universal machine- In a universal machine, in addition to the above four movements, the arm holding the drill head may be rotated on a horizontal axis. All this five movements in a universal machine enables it to drill on a w/p at any angle.
  16. 16. Gang Drilling Machine  When a number of single spindle drilling m/c columns are placed side by side on a common base and have a common worktable, the machine is known as the gang drilling m/c.  In it 4 to 6 spindle may be mounted side by side.  In some m/c the drill spindles are permentaly spaced on the work table, and in others the position of the columns may be adjusted so that the space between the spindles may be varied.  The speed and feed of the spindles are controlled independently.  This types of m/c is specially adapted for production work.  A series of operations may be performed on the work by simply shifting the work from one position to the other on the work table.  Each spindle may be set up properly with different tools for different operations.
  17. 17. Multiple Spindle Drilling Machine  The function is to drill number of hole in a piece of work simultaneously and to reproduce the same pattern of holes in number of identical pieces in a mass production work.  Such m/c have several spindles driven by single motor and all the spindles holding drills are fed into the work simultaneously.  Feeding motion is usually obtained by rising the work table, but the feeding motion also be secured by lowering the drill heads.  The spindles are so constructed that their centre distance may be adjusted in any position as required by various jobs within the capacity of the drill heads. For this purpose, the drill spindle are connected to the main drive by universal joints.  Drill jigs may be used for guiding the drills in mass production work.
  18. 18. Automatic Drilling Machine  It can perform a series of machining operations at successive units and transfer the work from one unit to the other automatically.  Once the work is loaded at the first machine, the work will move from one machine to the other where different operations can be performed and the finished work comes out from the last units without any manual handling.  This type of machine is intended purely for production purpose.
  19. 19. Deep Hole Drilling Machine  Special machines and drill are required for drilling deep holes in rifle barrels, crank shaft, long shafts etc.  The machine is operated at high speed and low feed.  Sufficient quantity of lubricant is pumped to the cutting points for removal of chips and cooling the cutting edges of the drill.  A long job is usually supported at several points to prevent any deflections.  The work is usually rotated while the drill is fed into the work. This helps in feeding the drill in a straight path. In some machines both the work and the drill are rotated for accurate location.  The m/c may be horizontal or vertical. The drill is withdrawn automatically each time when it penetrates into the work to a depth equal to its diameter, to permits the chip to clear out from the work.
  20. 20. Drilling Machine Operations 1. Drilling 2. Reaming 3. Boring 4. Counterboring 5. Countersinking 6. Spot facing 7. Tapping 8. Lapping 9. Trepanning 1. Drilling  It is the operation of producing a cylindrical hole be removing metal by the rotating edge of a cutting tool called the “drill”  Before drilling the centre of the hole is located on the work piece by drawing two lines at right angles to each other and then a centre punch is used to produce an indication at the centre.  The drill point is pressed at this centre point to produce the required hole.  Drilling does not produce an accurate hole in a w/p and the hole so generated by drilling becomes rough and the hole is always slightly oversize than the drill used due to the vibration of the spindle and the drill.
  21. 21. 2. Reaming  It is an accurate way of sizing and finishing a hole which has been previously drilled.  The speed of the spindle is made half that of drilling and automatic feed may be employed.  The tool used for reaming is known as the reamer which has multiple cutting edges.  Reamer cannot originate a hole. It simply follows the path which has been previously drilled and removes a very small amount of metal. 3. Boring  To enlarge a hole by means of an adjustable cutting tool with only one cutting edge. This is necessary where suitable sized drill is not available or where hole diameter is so large that it cannot be ordinarily drilled.  The cutter is held in a boring bar which has a taper shank to fit into the spindle socket.  For perfect finishing a hole, the job is drilled slightly undersized.
  22. 22. 4. Counterboring  It is a cylindrical flat-bottomed hole that enlarges another coaxial hole, or the tool used to create that feature.  This is necessary in some cases to accommodate the heads of bolts, studs, and pins. The tool used for counterboring is called counterbore.  The counterbores are made with straight or tapperd shank to fit in the drill spindle.  The cutting edges may have straight or spiral teeth.  The tool is guided by a pilot which extends beyond the end of the cutting edges.  The pilot fits into the small diameter hole having running clearance and maintains the alignment of the tool.  The pilot may be interchanged for enlarging different size of holes.  Cutting speed for counterboring is 25% less than that of drilling operations. A counterbore in a metal plate A cross-sectional diagram of a counterbore counterbore tools
  23. 23. 5. Countersinking  It is the operation of making a cone-shaped enlargement of the end of hole to provide a recess for a flat head screw or countersunk rivet fitted into the hole.  The tool used for countersinking is called a countersink.  Standard countersunks have 60°, 82° or 90° included angle and the cutting edges of the tool are formed at the conical surface.  The cutting speed in countersinking is 25% less than that of drill. Cross-sections of countersunk holes countersink A cross-sectional diagram of a countersinking
  24. 24. 6. Spot facing  It is the operation of smoothing the surface around a hole for the seat for a nut or the head of a screw.  A counterbore or a special spot facing tool may be employed for this purpose.
  25. 25. 7. Tapping  It is the operation of cutting internal threads by means of a cutting tool called a tap.  A tap may be considered as a bolt with accurate threads on it.  The threads act as cutting edges which are hardened and ground.  When the tap is screwed into the hole it removes metal and cuts internal threads which fit into external threads of the same size.
  26. 26. 8. Lapping  It is the operation of sizing and finishing a small diameter hole already hardened by removing a very small amount of material by using a lap.  The copper head laps are commonly used.  The lap fits in the hole and is moved up and down while it revolves. 9. Trepanning  It is the operation of producing a hole by removing metal along the circumference of a hollow cutting tool.  Trepanning operation is performed for producing large holes.  Fewer chips are removed and much of the material is saved while the hole is produced.  The tool resembles a hollow tube having cutting edges at one end and a solid shank at the other to fit into the drill spindle.
  27. 27. Types of the drill: 1. Flat or spade drill 2. Straight fluted drill 3. Two-lip twist drill a. Parallel shank – short series twist drill b. Parallel shank – stud series twist drill c. Parallel shank – long series twist drill d. Taper shank twist drill 4. Taper shank core drill (three or four fluted- not used to originate hole) 5. Oil tube drill 6. Centre drill
  28. 28. Nomenclature of Drill Tang Neck
  29. 29.  Flutes- The groove in the body of the drill which provides lip. Its functions are: - To form the cutting edges on the point. - To allow the chips to escape. - To cause the chips to curl - To permit the cutting fluid to reach the cutting edges.  Axis- The longitudinal centre line of the drill.  Body- The portion of the drill extending from its extreme point to the commencement of the neck (If present).  Body clearance- Portion of the body surface which is reduced in diameter to provide diametral clearance.  Heel- The edge formed by the intersection of the flute surface and the body clearance.  Lands- The cylindrically ground surface on the leading edges of the drill flutes.
  30. 30. Chisel edge- The edge formed by the intersection of the flanks. Also called “dead centre” Face- The portion of the flute surface adjacent to the lip on which the chip impinges as it is cut from the work. Flank- That surface on a drill point which extends behind the lip to the following flute. Lip- The edge formed by the intersection of the flank and face. Point- The sharpened end of the drill, consisting of all part of the drill which is shaped to produce lips, faces, flanks and chisel edge.  Shank- The part of the drill by which it is held and driven.  Tang- The flattened end of the taper shank intended to fit into a drift slot in the spindle, socket, or drill holder. Web- The central portion of the drill situated between the roots of the flutes and extending from the point toward the shank. Neck- The diametrically cut portion between the body and the shank of the drill.
  31. 31.  Chisel edge angle- The angle between the chisel edge and the lip as viewed from the end of the drill. The usual value of this angle varies 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 axis then there would be no rake but if the flute is right handed then it is positive rake and if it is left handed then the rake is negative. The usual value of rake angle is 30° to 45°. Smaller the rake angle, greater will be the torque required to drive the drill at a given feed. Lip clearance angle- The angle formed by the flank and a plane at right angles to the drill axis. It allow the drill to enter the metal without interference. A greater lip angle will cause the bit to cut more aggressively under the same amount of point pressure as a bit with a smaller lip angle
  32. 32. Nomenclature of Reamer
  33. 33.  Axis- The longitudinal centre line of the reamer.  Recess- That portion of the body which is reduced in diameter below the cutting edge, pilot or guided diameter.  Bevel lead angle- The angle formed by the cutting edges of the bevel lead and the reamer axis.  Clearance angles- The angle formed by the primary or secondary clearance and the tangent to the periphery of the reamer at the cutting edges.  Helix angle- The angle between the cutting edge and the reamer axis.  Rake angle- The angles, in a diametral plane formed by the face and a radial line from the cutting edges.  Taper lead angle- The angle formed by the cutting edges of the taper lead and the reamer axis.
  34. 34. Types of Reamer 1.Chucking Reamer with Parallel or Taper Shank  It has short and parallel cutting edges. It has a long body recess between shank and cutting edges. Reamer held in the spindle and driven by parallel or taper shank. The flutes are all straight and irregularly spaced around the circumference of the reamer body. This reduce the tendency to chatter (vibration).
  35. 35. 2. Chucking Reamer In this type of reamer the beveled edges remove the material. The cutting edges are chamfered at an angle of 45°. The body is provided slight taper. The diameter is reduced towards shank to avoid clogging of the reamer in the hole. .
  36. 36. 3.Machine Bridge Reamer It has parallel cutting edges and the flutes may be straight or helical It is used with portable electric or pneumatic tool for reaming in ship-building, structural, and plate work to make holes for riveting
  37. 37. 4. Machine Jig Reamer It has short and parallel cutting edges with bevel lead and a guide between the shank and cutting edges. The flutes are helical The plain part of the body accurately locates the reamer as it fits into a bushing in the jig.
  38. 38. 5. Parallel Hand Reamer with Parallel Shank It has virtually parallel cutting edges with taper and bevel lead The flutes are either straight or helical The square tang of the hand reamer facilitates hand operation for accurate sizing of the holes
  39. 39. 6. Socket Reamer  It has straight or taper shank It is may be driven by hand or machine The cutting edges having Morse taper are integral with shank The flutes may be straight or helical
  40. 40. 7. Shell Reamer It may be mounted on a arbor by an axial hole provided in the center It has virtually parallel cutting edges which are sharpened to form bevel lead It is employed for finishing large holes Numerous sizes of shells having similar internal hole size can be used on one arbor.
  41. 41. 8. Taper Pin Reamer It is employed for finishing the hole suitable for pins having a taper of 1 in 50 It has taper cutting edges and parallel or taper shank for holding and driving the reamer
  42. 42. 9. Expansion Reamer It is made in such a way that it may be adjusted to compensate for wear of the blades by very small amount The plug can be pushed further inside by loosening the clamping nut which forces the blades to expand by small amount
  43. 43. Tool-Holding Devices Drill press spindle provides means of holding and driving cutting tool End may be tapered or threaded for mounting drill chuck Most common Drill chucks Drill sleeves Drill sockets Drill Chucks Most common devices used for holding straight-shank cutting tools Most contain three jaws that move simultaneously when outer sleeve turned Hold straight shank of cutting tool securely Two common types Key Keyless
  44. 44. Chucks Hold straight-shank drills Mounted on drill press spindle Taper Threads - Held in spindle by self-holding taper in larger machines
  45. 45. Types of Drill Chucks Key-type  Most common  Three jaws move simultaneously when outer sleeve turned • Tighten with key Keyless  Chuck loosened or tightened by hand without key
  46. 46. Drill Sleeves and Sockets Drill Sleeves  Used to adapt cutting tool shank to machine spindle if taper on tool is smaller than tapered hole in spindle Drill Socket  Used when hole in spindle of drill press to small for taper shank of drill  Used also as extension sockets
  47. 47. Drill Drift Used to remove tapered-shank drills or accessories from drill press spindle Always place rounded edge up so this edge will bear against round slot in spindle Use hammer to tap drill drift and loosen tapered drill shank
  48. 48. Using the drill drift  The drift is inserted through a slot in the spindle Strike here to remove
  49. 49. Work-Holding Devices 1. T-bolt and clamps 2. Drill Press vise 3. Step block 4. Drill Jigs 1. T- bolts and clamps  Work directly clamped on table  T bolts fitted in T-slots provided on drilling machine table. 2. Clamps or straps  Used to fasten work to drill table or an angle plate for drilling Various sizes  Usually supported at end by step block and bolted to table by T-bolt that fits into table T-slot Modifications is gooseneck clamps Finger clamp U-clamp Straight clamp T- bolts
  50. 50. Finger clamp
  51. 51. 3. Goose neck clamp  Used for holding work of different height  Clamps made by forging so enough strong to withstand loads  Due to typical shape of clamp, it is possible to use smaller size of T-bolt for clamping the job 4. Drill vise  Used to hold round, square or odd-shaped, rectangular, pieces  Work is clamped between a fixed jaw and a movable jaw  While clamping the work in a vise, parallel blocks are placed under the work so that the drill may completely pass through the work without damaging the vise table.
  52. 52. 5. Step Blocks  To hold the work step block is used in combination with T-bolts and clamps  For different height of job, different steps of the step block are used. Clamping set
  53. 53. 6. Drill jigs  It is used to clamp and unclamp the components quickly in mass production  It hold the job securely, locate the work, and guide the tool at any desired position. 7. V blocks  It used for holding round job  Wok (job) may be supported on two or three blocks and clamped against them by straps and bolts. Drill jigs V blocks
  54. 54. Morse Taper Key less Chuck Chuck Chuck Key
  55. 55. Alignment Tests on Pillar Type Drilling Machine Before carrying out the alignment tests, the machine is properly levelled in accordance with the manufacturer’s instructions. The various tests performed are : 1. Flatness of clamping surface of base. (Refer Fig. 6.17). The test is performed by placing a straight edge on two gauge blocks on the base plate in various positions and the error is noted down by inserting the feeler gauges. This error should not exceed 0.1/1000 mm clamping surface and the surface should be concave only. 2. Flatness of clamping surface of table. This test is performed in the same manner as test (1), but on the table. The permissible error is also same.
  56. 56. 3. Perpendicularity of drill head guide to the base plate. The squareness (perpendicularity) of drill head guide to the base plate is tested : (a) in a vertical plane passing through the axes of both spindle and column, and (b) in a plane at 90° to the plane at (a). The test is performed by placing the frame level (with graduations from 0.03 to 0.05 mm/m) on guide column and base plate and the error is noted by noting the difference between the readings of the two levels. 4. Perpendicularity of drill head guide with table. This test is performed exactly in the same way as (b). (Refer above figure) and the permissible error is also same.
  57. 57. 5. Perpendicularity of spindle sleeve with base plate. This test is performed in both the planes specified in test (3) and in the similar manner with the difference that the frame levels are to be placed on spindle sleeve and base plate. The error (i.e., the difference between the readings of the two levels) should not exceed 0.25/1000 mm for plane (a) and the sleeve should be inclined toward column only ; and 0.15/1000 mm for plane (b).
  58. 58. 6. True running of spindle taper. For this test, the test mandrel is placed in the tapered hole of spindle and a dial indicator is fixed on the table and its feeler made to scan the mandrel. The spindle is rotated slowly and readings of indicator noted down. The error should not exceed 0.03/100 mm for machines with taper up to Morse No. 2 and 0.04/300 mm for machines with taper larger than Morse No. 2.
  59. 59. 7. Parallelism of the spindle axis with its vertical movement. This test is performed into two planes (A) and (B) at right angles to each other. The test mandrel is fitted in the tapered hole of the spindle and the dial indicator is fixed on the table with its feeler touching the mandrel. The spindle is adjusted in the middle position of its travel. The readings of the dial indicator are noted when the spindle is moved in upper and lower directions of the middle position with slow vertical feed mechanism.
  60. 60. 8. Squareness of clamping surface of table to its axis. For performing this test, the dial indicator is mounted in the tapered hole of the spindle and its feeler is made to touch the surface of table (Refer below Fig.). Table is slowly rotated and the readings of dial gauge noted down, which should not exceed 0.05/300 mm diameter. 9. Squareness of spindle axis with table. For this test a straight edge is placed in positions AA’ and BB’. Work table is arranged in the middle position of its vertical travel. The dial indicator is mounted in the spindle tapered hole and its feeler made to touch the straight edge first say at A and reading noted down. The spindle is rotated by 180° so that the feeler touches at point A’ and again reading is noted down. The difference of two readings gives the error in squareness of spindle axis with table. Similar readings are noted down by placing the straight edge in position BB’.
  61. 61. Cutting speed, V= D = Drill diameter, mm N = rotational speed of the drill, rpm MRR = Machining Time (Tm) = x = Tool approach = 0.29 D y = Tool over travel, 1 to 2 mm min
  62. 62. A hole of 30 mm diameter and 65 mm depth is to be drilled. The suggested feed is 1.3 mm per rev. and the cutting speed is 70 mpm. What are the spindle rpm, MRR and cutting time? Assume the clearance height is 5mm.
  63. 63. Spindle rpm= 744 Time= 0.0724 min MRR= 68.2479* 104

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