Machining Operations Performed On Turning Centers

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Machining Operations Performed On Turning Centers

by Mike Lynch

Copyright 2006 - CNC Concepts, Inc.

Table of contents: Navigating this eBook 4

Getting around 4 Licensing agreement 4 The importance of basic machining practice to CNC people 5 The three general turning applications 11

Shaft work 11 Chucking work 13 Bar work 14

How a cutting tool works 16 External versus internal work 17 Roughing versus finishing operations 18 Machining operations performed by single point cutting tools 20

Components of a single point cutting tool 22 The insert 22 The tool holder 24

Right hand versus left hand cutting tools 26 More about the geometry of a single point cutting tool 29

Lead angle, nose angle, clearance angle 29 Nose radius 30 Rake and relief angle 30

Other attributes of single point cutting tools 31 Chip breaker 31 Clamp and retaining pin 32 The difference between indexing and replacing an insert 32 Tool life 33 Chatter (vibration) 34 Part finish 34 Seat 34

How carbide inserts are specified 34

Machining Operations Performed On Turning Centers

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First letter (shape): 35 Second letter (relief angle): 35 Third letter (tolerances): 36 Fourth letter (type of insert) 37 First digit (size of insert) 37 Second digit (thickness) 38 Third digit (tool nose radius) 38

Understanding wear on single point cutting tools 38 Introduction to cutting conditions 41

The two ways to specify spindle speed 41 The two ways to specify feedrate 42 Getting recommendations for cutting conditions 43 Use of coolant 43

The machining process 45 Rough facing 46

More on depth-of-cut 46 Roughing facing all external raw material 47 Finishing stock – on diameters and faces 48 Cutting conditions for facing 48 Cutting tools used for rough facing 50 Sizing adjustments needed during the life of the rough facing tool 52

Rough Turning 52 More on depth-of-cut 53 Finishing stock – on diameters and faces 53

Cutting conditions for rough turning 54 Cutting tools used for rough turning 55 A note about back turning 57 Sizing adjustments needed during the life of the rough turning tool 58

Drilling 58 Cutting conditions for drilling 60

Other types of drills 60 Spade drills 60 Carbide insert drills 61 Sizing adjustments needed during the life of a drill 61

Rough boring 62 More on depth-of-cut 63 About length-to-diameter ratio 63 Finishing stock – on diameters and faces 64 Cutting conditions for rough boring 64 Cutting tools used for rough boring 66 Sizing adjustments needed during the life of the rough boring bar 67

Where we stand in the process 68 Finish facing and turning 69

A note about the finishing stock left on faces 70 Understanding surface finish requirements 70 Cutting conditions for finish facing and turning 72 Cutting tools used for finish facing and turning 73 Sizing adjustments needed during the life of the finish facing and turning tool 74

Machining Operations Performed On Turning Centers

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Finish boring 76 A note about the finishing stock left on faces 77 Understanding surface finish requirements 77 Cutting conditions for finish facing and turning 77 Cutting tools used for finish boring 78 Sizing adjustments needed during the life of the finish boring bar 78

Other common machining operations 79 Necking 79

Cutting conditions for necking 81 Parting 81 Threading 82

Cutting conditions for threading 84 Cutting tools for threading 84 Measuring threads 85 Machining internal threads 87

Sizing adjustments needed during the life of a threading tool 87

Websites that provide cutting tool information 88 Drilling 88 General information 88 Software 88