INDUSTRIAL TECHNOLOGY-METAL ASSOCIATED THEORY TOPIC4. MACHINE TOOLS & MACHINING INTRODUCTIONFIXED MACHINES DRILLING OPERATIONS LATHE ACCESSORIES TURINING.

INDUSTRIAL TECHNOLOGY-METALASSOCIATED THEORY

INDUSTRIAL TECHNOLOGY-METALASSOCIATED THEORY

TOPIC 4.

MACHINE TOOLS & MACHINING

INTRODUCTIONINTRODUCTION FIXED MACHINESFIXED MACHINES DRILLING OPERATIONS

DRILLING OPERATIONS

LATHE ACCESSORIES

LATHE ACCESSORIES

TURINING OPERATIONS

TURINING OPERATIONS BENCH GRINDERBENCH GRINDER

MILL DRILLMILL DRILL CENTRE LATHECENTRE LATHECUTTING TOOLSCUTTING TOOLS

MISCELANEOUS POWER TOOLS

MISCELANEOUS POWER TOOLS

INTRODUCTION

At the end of the 19th Century the Industrial Revolution launched many new ways of manufacturing. The introduction

of the ……………………. line, and the

development of ……………………… tools enabled work to be performed faster and sometimes more accurately. The use of assembly lines and machine tools to produce large quantities of identical items

 is called ………… …………………….

Machine tools in modern workshops are

powered by ……………………., either directly or via air compressors.

assembly

machine

mass production

electricity

Machine tools may be free-standing, e.g.,

…………..

 ………………….. and ……………………….

 or portable, e.g., …………………….. and

 …………… grinder. Battery powered electrical tools are known as

………………. power tools, and are popular on building sites, or for travelling repair and maintenance personnel. Voltages range from 7.5 to 18 volts.

lathe

bench grinder drilling machine

electric hand drill

angle

cordless

FIXED MACHINESCOLUMN DRILLING MACHINE

PULLEY GUARD

CHUCK

TABLE

MOTOR

FEED LEVER

COLUMN

TABLEADJUSTMENT

TWIST DRILL

REDUCED SHANK TWIST DRILL

COMBINATION CENTRE DRILL

COUNTERSINKING DRILL

General purpose drilling and for countersinking to a specific diameter.

This drill allows larger diameters to be drilled using a smaller capacity chuck.

Precise centring of holes drilled in the lathe.

Countersinking existing holes and deburring.

DRILL BITS

DRILLING OPERATIONSWhat type of steel are drills bits made from?

 ………………………………………….

 The general rule for drilling is:

Small drill ……………..speed.

Large drill …………….. speed.

 Why is it important to clamp work that is being drilled?

HSS (High Speed Steel)

fast

slow

The drill may catch the work as it breaks through, spinning the work around and may cause a serious injury.Do not use excessive force.Wear eye protection.Remove metal shavings with a brush.Avoid bent, blunt or damaged drill bits.

     Spindle motor Fast spindle speed     Spindle motor Slow spindle speed

Why is it important to use a centre punch before drilling?

When do you use cutting fluid?

What is a pilot hole, and how do you calculate the size of a pilot hole?

Prevent the drill running off centre.

Drilling large or deep holes in steel.

A small hole drilled before a larger hole. It’s diameter should be the width of the web.

MILL DRILL

This machine is a combination milling and drilling machine. In addition to holding a variety of different drill pieces it can also be used to machine flat surfaces on metal, cut grooves in shafts, and perform a variety of operations in the horizontal and vertical planes.

Horizontal feed Horizontal feed

Vertical feed Millingcutter

motor

THE CENTRE LATHE & TURNINGThe centre lathe is used for a variety of machining processes, including facing, turning between centres, drilling, knurling etc. It can hold various shaped materials using different chucks.

How should you be dressed when using the lathe ?

What particular precaution should be taken with the chuck key?

Why is it important not to interfere with the operator?

Leather covered shoes, apron tied, tie removed, loose clothing tucked in, and safety glasses. No jewellery.

Remove the key immediately after fitting or removing work from the chuck to prevent it being ejected.

A loss of concentration can result in a serious accident.

Leather covered shoes

Apron tied

Safety glasses

THE CENTRE LATHE

tool post

stand

dead centre

cross slide

compound rest

pulleys

bed

Automatic feed lever

guard

tailstockclamp

handwheel

live centre

feed rackapron hand wheel

quick changegearbox

tumblergears

back gearsleverheadstock

CUTTING TOOLS

What are cutting tools made from? 

When should a coolant be used? 

High Speed Steel (HSS)

When taking heavy cuts or when a high quality finish is required straight from the cutting tool.

Tool post screw

Tool post

Tool holder

T slot

Tool post clamped short

Cutting tool at centre height

Tool post ring

Tool post wedge

Knurling tool

Typical knurling pattern

Right hand Round nose Left hand

LATHE ACCESSORIES

CHUCKS

A general purpose chuck used for holding cylindrical and hexagonal work. A separate set of jaws (illustrated) can be fitted for large diameter work.

This chuck can hold square, octagonal or irregular shaped material. Each jaw can be reversed to suit the particular requirements.

3 Jaw self-centring chuck

4 Jaw Independent chuck

Key inserted here operates 3 jaws simultaneously.

Key inserted here operates this jaw independently.

LATHE ACCESSORIES

Revolving Centre Boring Bar

Parting Tool Holder Jacob’s chuck

Used to support long thin work when turning between centres.

A small cutting tool fitted to the end allows holes to be enlarged or reamed.

A thin HSS blade attached to this tool enables material to be cut off in the lathe.

This tool, fitted to the tailstock allows material to be drilled along the central axis.

TURNING OPERATIONSWhat special care must be taken when engaging automatic feed?

What is the purpose of the back gears ?

How is the size of the lathe determined?

Explain two methods that can be used to turn a taper.

Explain the difference between a roughing cut and a finishing cut.

 Roughing

Finishing

Automatic feed must be disengaged before the cutting tool collides with the chuck.

The maximum length of material that can be turned between centres and the maximum diameter material that can ‘swing” over the ways.1. Offset the tailstock so that the work is at an angle to

the axis of the lathe.

2. Adjust the compound rest to the required angle.

A deep, heavy cut that removes a large amount of material quickly, but leaves a rough surface.

A shallow or fine cut that removes only a small amount of metal and produces a smooth high quality finish.

A secondary set of gears which reduces the speed of the main spindle. These are used when turning large diameter work or when knurling.

BENCH GRINDER

What are grinding wheels made from?

 State two precautions to be observed when using the bench grinder.

How can uneven wear of the wheel be prevented?

How can grooves in the wheel be removed?

The two main types used in schools are aluminium oxide and silicon carbide.

1. Adjust the tool rest close to the wheel.

2. Stand to one side of the wheel when turning on.

Move the work from side to side across the face of the wheel.

A diamond pointed wheel dresser can be used to remove grooves.

GuardEye shield

Tool rest

Switch

MISCELANEOUS POWER TOOLS

Angle grinder

Portable drill

This model has a keyless chuck, variable speed, and reversing action, enabling it to be used as a screwdriver as well as a general purpose drill.

PRECAUTIONS

1. Use machine with both hands.

2. Direct sparks away from others.

3. Keep lead clear of the wheel.

4. Wait until machine stops before putting it down.

MISCELANEOUS POWER TOOLS

The portable saw

is useful for quickly cutting

tubular steel, angle iron, and

solid section up to  mm.

 It must be used with extreme care to avoid injury.

cut - off

20

1. Secure stock firmly in vice.

2. Apply firm but gentle pressure when cutting.

3. Wear eye and ear protection.

4. Warn students to avoid sparks before operating.

The cutting wheels are a composite of abrasive particles and reinforcing mesh fibre. Disconnect the power, remove the guard, lock the shaft and loosen the securing nut.