MACHINING+G11-SBQ+STUDY+MATERIAL.compressed

MACHINING TECHNOLOGY-II

SCHOOL BASED QUIZ STUDY MATERIAL

Grade 12 Term2

MACHINING TECHNOLOGY-II • • •

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MICROMETER

• Micrometer is used when a high level of accuracy is required.

• Micrometer has an accuracy of 0.01 mm • Most common micrometer measures up to 25mm.

13 Machining Technology II- EMM621–G11 term2 A.A-version 02-2015/2016

1.2.2 The Micrometer.

The micrometer is a measuring instrument that is used when a high level of accuracy is required.

http://www.youtube.com/watch?v=XQT6RSNN9sA

Fig.8 Micrometer

Easy to Remember

• • •

Clockwise direction

A-S-L-T-R-M-F

Accuracy-0.01mm

How to use micrometer

• Clean the surface • Place anvil at one

end. • Place spindle at

other end. • Turn the ratchet • Tight thimble


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PARTS OF LATHE MACHINE


3-Identify parts of the lathe and its operation. (Function) http://www.youtube.com/watch?v=dj64QvvbGXM


Fig-lathe machine parts


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QB Page6of10 G12-AEE-Subject

Solution:


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FUNCTIONS OF MILLING MACHINE PARTS

Part name Function

Head stock Provides driving power for rotation and contains spindle.

Bed Provides main frame for the support of the work-piece and tool during machining.

Carriage Controls and supports the cutting tool

Saddle Slides on bed

Apron Contains drive mechanism to move carriage

Cross slide Allows tool to move in and out

Compound rest Allows tool to move at an angle

Tool rest Used to mount the cutting tool

Feed mechanism Used to transmit power to carriage

Lead screw Used to transmit power to carriage through gear and clutch

Tail stock Supports long work pieces


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Part name Function

Head stock

Bed

Carriage

Compound rest

Lead screw

Tail stock

Lathe attachments


3.1 Headstock

Head stock provides the driving power to control the rotation of the part (workpiece) being machined. The headstock contains the spindle to which the various work-holding attachments are fitted

3.2 Bed

Its function is to provide main frame for the support of the work-piece and tool during machining.

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Machining Technology II- EMM621–G11 term2 A.A-version 02-2015/2016

3.1 Headstock

Head stock provides the driving power to control the rotation of the part (workpiece) being machined. The headstock contains the spindle to which the various work-holding attachments are fitted

3.2 Bed

Its function is to provide main frame for the support of the work-piece and tool during machining.


3. 3. Carriage

Controls and supports the cutting tool, and composed of a number of parts. x The saddle is fitted to the ways of the bed and slides along them (Z axis for CNC machines). x The apron contains a drive mechanism to move the carriage along the ways, using hand or power feed. x The cross-slide allows the tool to move in and out (toward or away from the operator), (X axis for CNC machines). x The compound rest allows the tool to move at an angle. (move in X and Z axes at the same time) x The tool rest is used to mount the cutting tool.

Power is transmitted to the carriage through the feed mechanism. This regulates the amount of tool travel per revolution of the spindle (Feed).


Tool holder

Compound rest

3.4 .Lead screw: Lead screw transmits power to the carriage through a gearing and clutch arrangement in the carriage apron


Tool holder

Compound rest

3.4 .Lead screw: Lead screw transmits power to the carriage through a gearing and clutch arrangement in the carriage apron


3.5 .Tailstock .the function of the tailstock is to support long work-pieces during machining, and to hold some cutting tools. Turning the hand wheel of the tailstock clockwise advances the spindle (which holds the cutting tools or center) toward the workpiece.

3.6. Lathe attachments:

An attachment is a device mounted on the lathe so that a wider range of operations could be performed


3.5 .Tailstock .the function of the tailstock is to support long work-pieces during machining, and to hold some cutting tools. Turning the hand wheel of the tailstock clockwise advances the spindle (which holds the cutting tools or center) toward the workpiece.

3.6. Lathe attachments:

An attachment is a device mounted on the lathe so that a wider range of operations could be performed


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LATHE CUTTING TOOLS

Part name Function

High carbon steel

High speed steel

HSS Solid

H.S.S. butt welded onto a medium carbon steel shank.

Tungsten carbide Brazed tip

Indexable inserts


4-Lathe cutting tools selection and setup. http://www.youtube.com/watch?v=J63dZsw7Ia4

In order that metal may be cut effectively and efficiently the choice of cutting tool is very important. The cutting edge must be sharp, have adequate support and be made from a suitable material. All lathe cutting tools must be hard enough to maintain a cutting edge and tough enough to withstand shock and heavy pressure.

4.1-Materials used for lathe cutting tools

1-High carbon steel

High carbon steel was once commonly used, but has now been replaced by high speed steel and other alloys since these materials keep their cutting edge for longer periods.


2-High speed steel (H.S.S.)

High speed steel tools are the most widely used cutting tool materials in engineering. H.S.S. is used for lathe tools, drills, taps, reamers and milling cutters.

Lathe tools can be any of the three types:

1. H.S.S. butt welded onto a medium carbon steel shank.

2. H.S.S. tool bits held in tools holders.

3. H.S.S. solid tool (shank and cutting edge made from H.S.S)

H.S.S. tool bits held in tools holders.


H.S.S. solid



H.S.S. solid



3-Tungsten carbide

The use of tungsten carbide tools has increased greatly. This material is considerably harder than high speed steel therefore higher cutting speeds are possible.

The two types of tungsten carbide tools available are:

1. Brazed tip

The method of securing the tip to the shank is by brazing. When these tools are worn it is necessary to regrind them on a special type of grinding wheel.


2. Indexable inserts

The method of securing the insert is by clamping; when a cutting edge is worn the tip can be turned around and accurately clamped in position for another cutting edge to be presented to the workpiece.

When using tungsten carbide tools observe the following:

4. The lathe must be rigid and free from vibration. 5. The power and speeds available must be adequate to allow the tool to be used at high rates of metal removal. 6. The tool must not be allowed to rub and the feed disengaged before the spindle is stopped.


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SELECTION OF CUTTING TOOLS

Selection of cutting tools based on

• Material • Maximum cutting temperature • Cutting speed • Cutting depth • Purpose • Tool material • Shape

CORRECT SETTING OF CUTTING TOOL

CUTTING TOOL SHAPE


3. Set the tool by eye to about centre height, take a very light facing cut down to the centre of the material, stop the machine and adjust the tool height to the centre of the material.

This is the correct setting for cutting tool

Too much Overhang over the centre


4.4-Lathe cutting tools shape and forms.

4.4.1-Lathe tool shapes.

When planning the operation procedure, the choice of tool shape and type is dependent on the type of machining required on the workpiece Fig.

below shows a range of tool shapes and the machining operations they perform.

1. Screw cutting. 2. Knurling. 3. Parting. 4. RH(Right Hand) 5. LH (Left Hand). 6. RH Knife. 7. LH Knife. 8. Turning. 9. Round Nose. 10. Boring.


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WORK HOLDING DEVICE

3 jaw self centering chuck

Holds cylindrical or hexagonal work. All three jaws move together to bring the work on center.

4 Independent chuck

Four jaws are reversible and can hold work of different sizes and shapes. Each jaw may be moved independently.


Right Hand

Left Hand

Head stock

Tailstock

Operator facing the lathe

Roughing Roughing Turning Facing Facing Turning

Right-hand tools

Left-hand tools

Round nose turning tool


5- Work holding for lathe cutting operations.

When work has to be machined there must be no possibility of the workpiece moving due to the forces exerted during the machining operation. Accessories for the lathe are available for a wide range of operations. These include devices for holding the work securely and devices for supporting the work during machining.

There are two main types of chucks used to hold the work in turning applications:

1. The three jaw self-centring chuck 2. The four jaw independent chuck

5.1- 3 Jaw self-centering chuck

The three-jaw universal chuck holds cylindrical or hexagonal work. All three jaws move together to bring the work on center. Two sets of interchangeable jaws are provided as the jaws are not reversible, these are called inside and outside jaws. One set is used to grip the work inside while the other is used to grip the work on the outside.


5- Work holding for lathe cutting operations.

When work has to be machined there must be no possibility of the workpiece moving due to the forces exerted during the machining operation. Accessories for the lathe are available for a wide range of operations. These include devices for holding the work securely and devices for supporting the work during machining.

There are two main types of chucks used to hold the work in turning applications:

1. The three jaw self-centring chuck 2. The four jaw independent chuck

5.1- 3 Jaw self-centering chuck

The three-jaw universal chuck holds cylindrical or hexagonal work. All three jaws move together to bring the work on center. Two sets of interchangeable jaws are provided as the jaws are not reversible, these are called inside and outside jaws. One set is used to grip the work inside while the other is used to grip the work on the outside.


5.2- 4 independent chuck.

The four jaws are reversible and can

hold work of different sizes and shapes.

Each jaw may be moved independently.

3 jaw- move together

4 jaw- move independently


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BASIC LATHE OPERATIONS

Facing

Removing material from end face to bring the work piece to desired length

Parallel turning

Moving the cutting tool parallel to work piece axis in order to reduce its diameter.

Finish turning

Producing a good surface finish

Knurling

Impressing a pattern into the surface of a work piece to either improve its appearance or to provide a better gripping surface.


6. Perform basic lathe machine operations. http://www.youtube.com/watch?v=9dk0qZFLKvo

Metal Lathes are used to make most of the accurate circular metal parts you see today. The general name for all Lathe operations is TURNING:

x Facing x Parallel turning x Knurling x Taper turning x Drilling x Threading x Grooving or Recessing x Boring


In this term you will be taught some of these operations 6.1-Facing: This is the name of the process on a Lathe used to remove a small amount of material (around 1 – 2 mm) from the end of the workpiece. This is used to produce smooth and true face and also to bring the workpiece to the desired length.

http://www.youtube.com/watch?v=AmeZxnDA580&feature=endscreen

6.2-Parallel turning: This is the process to move the cutting tool parallel to the workpiece axis in order to reduce its diameter.

This axis is called Z axis). Parallel turning could be rough turning or finish turning.Fig. bellow shows parallel turning operation and turning cutting tool. http://www.youtube.com/watch?v=5zqLHPnp8zw

a. Rough Turning.

Rough turning is used to remove most of the excess material as quickly as possible and to true the work diameter.

b. Finish Turning.

The purpose of finish turning is to bring the workpiece to the required size and to produce a good surface finish. Generally only one finish cut is required since no more than 0.8 – 1.3 mm should be left on the diameter for the finish cut, but regarding OPTIMUM lathe which we have in our workshops and due to its size, the finishing cut should not be more than 0.5 mm.

Fig. Parallel Turning






a. Rough Turning.


b. Finish Turning.








a. Rough Turning.


b. Finish Turning.




6.3- Knurling. https://www.youtube.com/watch?v=dTmv_kYimrI Knurling is a process of impressing a pattern into the surface of a workpiece to either improve its appearance or to provide a better gripping surface. Almost all items that have to be tightened by fingers are knurled or items which are handled such as plug gauges. There are two patterns of knurling which may be produced:

1. a straight pattern. 2. a diamond pattern.


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Drilling

Drilling hole in work piece.

Threading

To make spiral or helical cuts

Tapping

Process of cutting an internal thread

Die cutting

Process of cutting external threads


6.4.2- drilling. https://www.youtube.com/watch?v=xfQWKmq2NhA Before attempting any drilling operation on the centre lathe, the workpiece should be faced and centre drilled. An uneven face or starting to drill a hole without a centre will cause the drill to run off centre.

The two types of drills commonly used are,

1. Straight shank. the straight shank drill is fitted into a drill chuck.

2. Morse taper shank drills. The Morse taper shank drill fits directly into the tailstock barrel.


6.5 Threading: http://www.gettyimages.ae/detail/video/machine-drilling-into-metal-stock-footage/89633704

This is the name of the process to make spiral or helical cuts on a material. These cuts are usually found on bolts (external thread) or

nuts (internal thread).Threading can be done by hand using tools called TAPs and DIEs or they can be done at speed on the lathe using

thread cutting tools.

6.5.1-Parts of a thread

For identifying different types of thread, the following names are given to its different parts. 54

Machining Technology II- EMM621–G11 term2 A.A-version 02-2015/2016

6.5.2- Taps and tapping: Tapping is the process of cutting an internal thread.

6.5.3Dies and die cutting:

This is the process of cutting external threads onto round bar


6.5.2- Taps and tapping: Tapping is the process of cutting an internal thread.

6.5.3Dies and die cutting:

This is the process of cutting external threads onto round bar


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STANDARD BS308

A common code of standards and conventions for engineering drawings is described by British standard BS308

LINE TYPES


1. Determine job requirements 1.1 Read Engineering Drawing Standards, Common Symbols and abbreviations

It is difficult and time consuming to draw complicated details such as screw threads. It is much easier to use a standard convention as illustrated below Fig. 1 A common code of standards and conventions for engineering drawings is described by British Standard 308 engineering drawing practice and its international equivalents. Always use the accepted standards and conventions in drawings. This includes types of lines used, conventions for common features, abbreviations for written statements, dimensioning, cross-sectioning and machining symbols. Fig.1 Screw thread convention

MACHINING TECHNOLOGY-II

STANDARD – BS 308

A common code of standards and conventions for engineering drawings is described by

BS 308 Engineering drawing (British Standard)

LINE TYPES


1. Determine job requirements 1.1 Read Engineering Drawing Standards, Common Symbols and abbreviations

It is difficult and time consuming to draw complicated details such as screw threads. It is much easier to use a standard convention as illustrated below Fig. 1 A common code of standards and conventions for engineering drawings is described by British Standard 308 engineering drawing practice and its international equivalents. Always use the accepted standards and conventions in drawings. This includes types of lines used, conventions for common features, abbreviations for written statements, dimensioning, cross-sectioning and machining symbols. Fig.1 Screw thread convention


1.1.1 Linotypes. Two types of line are used on engineering drawings. They are “thick” and “thin”. On pencil drawings it may be assumed that thick lines are twice the thickness of thin lines. The various types of lines are shown in Fig. 2 A full description of standard conventions is provided in British Standard 308 and the International Organisation for Standardisation (ISO).

Fig.2 Types of line BS 308.


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COMMON CONVENTIONS

2

COMMON CONVENTIONS


1.1.2 Conventions common features.

Some conventional methods for representing common features on engineering drawings are given in Fig.3 they are from BS 308.


Fig. 3 Conventions for some common features

2

COMMON CONVENTIONS


1.1.2 Conventions common features.

Some conventional methods for representing common features on engineering drawings are given in Fig.3 they are from BS 308.


Fig. 3 Conventions for some common features


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ABBREVIATIONS AND SYMBOLS

TOLERANCE

Tolerance is allowable variation of a given size. It is the difference between largest and smallest permissible dimensions.

FIT

Fit is the range of tightness designed into parts which assemble one into another.

1. Clearance fit: One part fits into another part with a clearance gap. Shaft size smaller than hole. Assembled by aligning hole and shaft

3

ABBREVIATIONS AND SYMBOLS BS308

R: Radius of circle

φ : Diameter of circle

P: Pitch of thread

M: Metric Thread

mm: Millimeter

Example: M10 × 1.5

This means Screw (metric thread) with diameter 10 and thread pitch 1.5


Fig.6 Abbreviations in common use


1.1.3 Abbreviation and Symbols: BS 308

A selection of symbols and abbreviations for terms in common use on general engineering drawings appears in Fig. 4

Common Symbols and abbreviations: R: Radius of a circle. 4 Ø: Dia. = Diameter. Fig. 5 TYP: Typical dimensions. Fig. 5

Fig.4 Fig.5

P: Pitch of the thread Fig. 6 mm: the unit of measurement is millimeter M: Metric Thread

Example: M10 X 1.5: M = metric thread (Screw) 10 = diameter, 1.5 = Thread pitch Fig.6





Fig.4 Fig.5







Fig.4 Fig.5



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TOLERANCE

Tolerance is allowable variation of a given size. Tolerance is the difference between largest

and smallest permissible dimensions.

Largest permissible dimension = 70+0.1= 70.1

Smallest permissible dimension = 70-0.3=69.7

Tolerance = 70.1-69.7 = 0.4mm

FIT


1. Clearance fit: One part fits into another part with a resulting clearance gap.

The shaft will be always smaller than hole.

Mating components may be assembled by aligning the hole and shaft.


Example 02


1.3- Tolerances and fits.

1.3.1 Tolerance http://www.youtube.com/watch?v=EsJkjEIh-mw

When a piece of machinery is made of many parts it is important that all the parts FIT together correctly. Parts must also be interchangeable. For example, when parts of car engines are replaced they do not require any extra machining. To make sure that parts fit correctly limits are added to the dimensions of each piece. It will be noticed that on engineering drawings you can often see plus + and minus – signs placed one above the other ± followed by a set of numbers such as ± 0.5 mm. For example, if a shaft is shown on a drawing as 25 ±0.5 mm this means that the biggest size the shaft can be is 25.05 mm and the smallest size the shaft can be is 24.95 mm.

The difference between these two sizes is called the tolerance.

From the Fig. below the following can be Calculated:

1. The largest permissible dimension = 70.1 mm (70 + 0.1 = 70.1 mm)

2. The smallest permissible dimension = 69.7 mm (70 – 0.3 = 69.7 mm)

3. The tolerance = 0.4 mm (70.1 – 69.7 = 0.4 mm)


By adjusting the tolerance we can get different types of fit. There are three classes of fits, they are:

1. Clearance fit

Mating components may be assembled by aligning the hole and shaft. The shaft will always be smaller than the hole (This is when the biggest shaft will enter the smallest hole without force).

7

TOLERANCE

Tolerance is allowable variation of a given size. Tolerance is the difference between largest

and smallest permissible dimensions.

Largest permissible dimension = 70+0.1= 70.1

Smallest permissible dimension = 70-0.3=69.7

Tolerance = 70.1-69.7 = 0.4mm

FIT


1. Clearance fit: One part fits into another part with a resulting clearance gap.

The shaft will be always smaller than hole.

Mating components may be assembled by aligning the hole and shaft.


Example 02


1.3- Tolerances and fits.

1.3.1 Tolerance http://www.youtube.com/watch?v=EsJkjEIh-mw

When a piece of machinery is made of many parts it is important that all the parts FIT together correctly. Parts must also be interchangeable. For example, when parts of car engines are replaced they do not require any extra machining. To make sure that parts fit correctly limits are added to the dimensions of each piece. It will be noticed that on engineering drawings you can often see plus + and minus – signs placed one above the other ± followed by a set of numbers such as ± 0.5 mm. For example, if a shaft is shown on a drawing as 25 ±0.5 mm this means that the biggest size the shaft can be is 25.05 mm and the smallest size the shaft can be is 24.95 mm.

The difference between these two sizes is called the tolerance.

From the Fig. below the following can be Calculated:

1. The largest permissible dimension = 70.1 mm (70 + 0.1 = 70.1 mm)

2. The smallest permissible dimension = 69.7 mm (70 – 0.3 = 69.7 mm)

3. The tolerance = 0.4 mm (70.1 – 69.7 = 0.4 mm)


By adjusting the tolerance we can get different types of fit. There are three classes of fits, they are:

1. Clearance fit

Mating components may be assembled by aligning the hole and shaft. The shaft will always be smaller than the hole (This is when the biggest shaft will enter the smallest hole without force).


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2. Interference fit: One part is forcible fit into another. Shaft is always larger than hole. Assembled by press or hammer

3. Transition fit: Loose- clearance Tight- Interference

Assembled by light press or hammer

COMPONENTS OF A THREAD

8

2. Interference fit: One part must be forcibly fitted into another. The shaft is always larger than hole. Mating components may be assembled by press or hammer blows.

3. Transition fit: Loosest case provides a clearance fit and tightest case gives interference

fit. Mating components may be assembled by light press

or a hammer tap.

INTRODUCTION TO LATHE MACHINE

Centre lathe is a power-driven, general-purpose machine tool used for producing cylindrical

work-pieces. As the piece of metal to be machined is rotated in the lathe, a single-point cutting

tool is advanced radically into the work-piece at specified depth and moved longitudinally along

the axis of the work-piece, to remove the metal in form of chips in order to make the required

shape.


2. Introduction to lathe machine

Introduction

The centre lathe is a power-driven, general-purpose machine tool used for producing cylindrical work-pieces. As the piece of metal to be machined is rotated in the lathe, a single-point cutting tool is advanced radically into the work-piece at specified depth and moved longitudinally along the axis of the work-piece, to remove the metal in form of chips in order to make the required shape. Fig. shows the principles of lathe machine work.


3. Interference fit With the interference fit a press or hammer blows are required for the assembly of the mating parts. The shaft is always larger than the hole but unlikely to damage or overstrain the components (This is when the smallest shaft will not enter the biggest hole).


2. Transition fit

Transition fits may require a light press, or a hammer tap since there may be interference or clearance between the mating parts (The tolerances will give either interference or a clearance fit).


6.5 Threading: http://www.gettyimages.ae/detail/video/machine-drilling-into-metal-stock-footage/89633704

This is the name of the process to make spiral or helical cuts on a material. These cuts are usually found on bolts (external thread) or

nuts (internal thread).Threading can be done by hand using tools called TAPs and DIEs or they can be done at speed on the lathe using

thread cutting tools.

6.5.1-Parts of a thread

For identifying different types of thread, the following names are given to its different parts.

8

2. Interference fit: One part must be forcibly fitted into another. The shaft is always larger than hole. Mating components may be assembled by press or hammer blows.

3. Transition fit: Loosest case provides a clearance fit and tightest case gives interference

fit. Mating components may be assembled by light press

or a hammer tap.

INTRODUCTION TO LATHE MACHINE

Centre lathe is a power-driven, general-purpose machine tool used for producing cylindrical

work-pieces. As the piece of metal to be machined is rotated in the lathe, a single-point cutting

tool is advanced radically into the work-piece at specified depth and moved longitudinally along

the axis of the work-piece, to remove the metal in form of chips in order to make the required

shape.


2. Introduction to lathe machine

Introduction

The centre lathe is a power-driven, general-purpose machine tool used for producing cylindrical work-pieces. As the piece of metal to be machined is rotated in the lathe, a single-point cutting tool is advanced radically into the work-piece at specified depth and moved longitudinally along the axis of the work-piece, to remove the metal in form of chips in order to make the required shape. Fig. shows the principles of lathe machine work.


3. Interference fit With the interference fit a press or hammer blows are required for the assembly of the mating parts. The shaft is always larger than the hole but unlikely to damage or overstrain the components (This is when the smallest shaft will not enter the biggest hole).


2. Transition fit

Transition fits may require a light press, or a hammer tap since there may be interference or clearance between the mating parts (The tolerances will give either interference or a clearance fit).


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KNURLING PATTERNS

FORM TOOL

Small radii, chamfers, grooves and undercuts are conveniently formed on a work piece by using a form tool. The tool is ground to the required radius or contour and set rigidly into the tool post. To produce a good finish, the work should be revolved slowly while soluble oil is applied as the tool is fed into the work.


6.3- Knurling. https://www.youtube.com/watch?v=dTmv_kYimrI Knurling is a process of impressing a pattern into the surface of a workpiece to either improve its appearance or to provide a better gripping surface. Almost all items that have to be tightened by fingers are knurled or items which are handled such as plug gauges. There are two patterns of knurling which may be produced:

1. a straight pattern. 2. a diamond pattern.


4.4.2- Form Lathe tool.

Small radii, chamfers, grooves and undercuts are conveniently formed on a workpiece by using a form tool. The tool is ground to the required radius or contour and set rigidly into the tool post. To produce a good finish the work should be revolved slowly while soluble oil is applied as the tool is fed into the work.


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TOOL CENTRE HEIGHT

PRACTICAL TASK

From the drawings above answer the following questions:

1. What is the revision number of the most recent drawing? 2

2. When was the drawing updated? 18/11/2012


4.3- Setting tools on centre height https://www.youtube.com/watch?v=vpCu56O8AJ0

All tools that are to be used on a centre lathe must be set to the centre line of the machine, called centre height. There are a few ways this can be achieved.

1. Position the tools to the headstock or tailstock centre and adjust until the tool point is in line with the centre point.

2. Lightly trap a small rule between the work and the tool point. When the tool is on centre the ruler will be vertical.


4.3- Setting tools on centre height https://www.youtube.com/watch?v=vpCu56O8AJ0

All tools that are to be used on a centre lathe must be set to the centre line of the machine, called centre height. There are a few ways this can be achieved.

1. Position the tools to the headstock or tailstock centre and adjust until the tool point is in line with the centre point.

2. Lightly trap a small rule between the work and the tool point. When the tool is on centre the ruler will be vertical.


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3. What tool is now required for this revision? Knurling tool

4. What material is needed for the handle? Aluminium

5. What is the maximum diameter of the handle? D20

6. What is the diameter of the stepped section of the handle? D12

7. What is the overall length of the handle? 24

8. What is the length of the stepped section? 10

9. What is the angle of the chamfered edges? 45 degree

10. What is the depth of the threaded hole? 8 mm

11. What drill size is needed for the threaded hole? 5 mm

12. What TAP size is needed for the thread? 6 mm

13. What does this symbol on the drawing mean? Third angle projection

14. What is the scale of the drawing? 2:1

15. What is the tolerance of the drawing? +/-1mm

Look at the Small Handle drawing and put the following planning stages in the correct order. It maybe has different orders and it must be reasonable and logical order.

Answer: 1-13-8-5-2-6-4-11-9-7-3-10-12-14-15


Part 2: Plan for Manufacture. Before machined [15marks]

Look at the Small Handle drawing and put the following planning stages in the correct order. It maybe has different orders and it must be reasonable and logical order.

Planning Stage Order 1 Make sure that the workshop is ready to be used 1 2 Tap the M6 blind hole 3 Check that the step diameter is 12 mm and step length is 10 mm 4 Face off the second side 5 Saw the Aluminum bar to 26mm length if applicable 6 Check the accuracy of the turned length is 24mm (±1mm tolerance) 7 Face off one side 8 Centre drill one side 9 Chamfer 2mm on one side (taper turn) 10 Step turn down to 12 mm for 10 mm length 11 Set up and inspect the Lathe 12 Chamfer 2mm on the other side (taper turn) 13 Drill a hole in one end 5mm diameter x 8mm deep 14 Knurl the handle grip

15 Clean the machine and storage the tools correctly 15

Key Words: Lathe, tap wrench, tap, drill bit, tailstock, facing tool, turning tool, Vernier calipers, Centre drill, tailstock, tool post, hacksaw, bench vice, knurling tool

(___/15)


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MICROMETER READING EXAMPLE

QB Page9of10 G12-AEE-Subject

Solution:a)5.00+0.50+0.28=5.78mmMicrometerreading=5.78mmb)5.00+0.28=5.28mmMicrometerreading=5.28mmc)12.00+0.50+0.16=12.66mmMicrometerreading=12.66mmd)7.00+0.50+0.26=7.76mmMicrometerreading=7.76mm

ATM 412 – Machining

14 Module 1: Introduction to Machining

Example 1:

Fig. 1.28 (a) shows example 1 of a

micrometer reading.

Steps of solution:

!!

Example 2:

Fig. 1.28 (b), shows example 2 of a

micrometer reading.

!Steps of solution:

!!

3.2.5 Digital micrometers Digital micrometers are also available to give

direct reading. Fig 1.29

!!!!

Fig. 1.28 (a): Micrometer

reading = 5.78 mm

Fig. 1.28 (b): Micrometer

reading = 5.28 mm

Fig. 1.29: Digital Micrometer

5.00 + 0.50 + 0.28 _______ 5.78 mm _______ _______

5.00 + 0.28 _______ 5.28 mm _______ _______

ATM 412 – Machining

14 Module 1: Introduction to Machining

Example 1:

Fig. 1.28 (a) shows example 1 of a

micrometer reading.

Steps of solution:

!!

Example 2:

Fig. 1.28 (b), shows example 2 of a

micrometer reading.

!Steps of solution:

!!

3.2.5 Digital micrometers Digital micrometers are also available to give

direct reading. Fig 1.29

!!!!

Fig. 1.28 (a): Micrometer

reading = 5.78 mm

Fig. 1.28 (b): Micrometer

reading = 5.28 mm

Fig. 1.29: Digital Micrometer

5.00 + 0.50 + 0.28 _______ 5.78 mm _______ _______

5.00 + 0.28 _______ 5.28 mm _______ _______


� 19

DRILL

READING A DRAWING


6.4- Drilling on lathe machine. 6.4.1 Centre drilling. https://www.youtube.com/watch?v=QUQkMwvTbKg Centre drilling is performed on a workpiece to either produce a location for a machine centre or to provide an accurate start before drilling. The end of the workpiece must be square and flat before centre drilling. This can be achieved by taking a facing cut first.

Centre Drill

A. Look at the drawing below, then answer the following

questions.

What is the used material?

What is the diameter of the through hole?

The unit of measurement is

What is dimension A? What is dimension C?

Aluminum 16 mm Milli-meter 124-(50+48)=26mm 75-30 = 45 mm

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