Geometric Dimensioning and Tolerancing for Mechanical Design Part 14 docx

TABLE A-1 Oversize Diameters in Drilling∗ Amount oversize, inch Drill diameter, inch Average max.. ∗Machinery’s Handbook, Revised 21st Edition, Industrial Press Inc.. 248 AppendixTABLE A

TABLE A-1 Oversize Diameters in Drilling∗

Amount oversize, inch Drill diameter, inch Average max Mean Average min

∗Machinery’s Handbook, Revised 21st Edition, Industrial Press Inc.

247

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248 Appendix

TABLE A-2 Machine and Cap Screw Sizes

A

Hex head

machine

screws

A

Socket head

cap screws

A

Round head

machine

screws

∗Clearance Hole Ø @ LMC is calculated with the formula (Fastener+ Fastener head) / 2

Appendix 249

TABLE A-3 Number, Letter, and Fractional Drill Sizes

Drill no Fract Deci Drill no Fract Deci Drill no Fract Deci Fract Deci

250 Appendix

TABLE A-4 Inch to Millimeter Conversion Chart

Appendix 251

Actual Positional Diameter – Z

(On the Drawing) Basic Dimension

Y Direction Difference

Actual Measured Location

Datum Plane

Actual Measured Location

True Position

(On the Drawing)

Basic Dimension

2 2

X + Y

Z = 2 Conversion Formula

X Direction Difference Actual Feature Axis

Figure A.1 Conversion diagram from coordinate measurements to cylindrical tolerance (The Coordinate Conversion Table is on the next page.)

TABLE A-5 Conversion of Coordinate Measurement to Cylindrical Tolerance

Z Diameter Positional Tolerance Y

D

i

r

e

c

t

i

o

n

D

e

v

i

a

t

i

o

n

X Direction Deviation

Actual mating envelope, 30

Advantages of GD&T, 3

All around symbol, 26, 189

ALL OVER note, 189

American National Standards Institute, 1

Angularity, 93

Application of datums, 49

Arc length symbol, 29

Basic dimension, 4, 26, 31, 188

Between symbol, 25, 189

Bonus tolerance, 6, 23, 108

Boundary, 141

Boundary conditions, 113

CAD/CAM database models, 14, 225

Calculation of wall thickness, 113, 114

Circular Runout, 177

Circularity, 76

Clearance hole size at least material

condition, 127 Clocking, 234, 238

Coaxiality, 157

Coaxiality at maximum material condition,

159 Composite feature control frame, 21, 135, 195

Composite positional control of coaxial

features, 160 Composite positional tolerancing, 135

Composite profile, 195

Conical taper, 28

Controlled radius symbol (CR), 28

Coordinate conversion diagram, 251

Coordinate conversion table, 252

Coordinate dimensioning and tolerancing, 3

Coplanarity, 192

Counterbore symbol, 26

Counterbored holes, 139

Countersink symbol, 26

Cylindrical datum features, 52

Cylindrical tolerance zone, 4

Cylindricity, 78

Data graph, 210, 213

Datum, 31, 47

Datum feature, 31 Datum feature identification, 51 Datum feature of size, 54 Datum feature of size specified at MMC & RFS, 55

Datum feature selection, 51 Datum feature simulator, 31 Datum Feature Symbol, 19 Datum reference frame, 48, 105 Datum targets, 25, 59

Datum target areas, 59, 61 Datum target lines, 59, 61 Datum target points, 59 Equalizing datums, 61 Step datums, 61 Datum targets established on a cylindrical part, 60

Datums specified in order of precedence,

6, 48 Definition of coaxiality, 157 Depth symbol, 27

Diamond shaped pin, 239 Dimension origin symbol, 27 Dimensional limits, 14 Drill sizes chart, 249 Face and diameter datums, 179 Fasteners 126, 128

Feature, 31 Feature control frame, 20 Feature control frames specified with MMC, 23

Feature control frames specified with RFS, 22

Feature of size, 31 Feature subject to size variations, 31 Features controlled to datum features of size,

54, 55 Features not subject to size variations, 54 Features subject to size variations,

54, 55 Fixed and double fixed fasteners, 128 Fixed fastener formula, 129

Flatness, 69 Unit flatness, 71

253

Copyright © 2006 by Gene R Cogorno Click here for terms of use.

254 Index

Floating fastener formula, 126

Form, 18, 69

Free state variation symbol, 25

Free state variation, 78

Full indicator movement (FIM), 169, 183

Functional gage, 109, 238, 239

Gage sketch (cartoon gage), 236

Geometric Characteristic Symbols, 18

Geometric controls to refine datum features,

229, 232, 235 Geometric Dimensioning and Tolerancing, 2

Geometric form, 69

Graphic analysis, 207

Immobilization of a part, 48

Implied datums, 3

Inch and millimeter dimensions, 10

Inclined datum features, 52

Inspecting a hole location, 105

Least material condition (LMC), 32, 112

Least material condition modifier (circle L),

24, 32, 112 Location, 18

Material conditions, 22

Maximum material condition (MMC), 32, 55,

108, 226 Maximum material condition modifier

(circle M), 23, 107 Measurement

Angular, 11 Linear, 11 Multiple datum features, 57, 179

Multiple patterns of features, 132

Noncircular features at MMC, 141

Nonparallel holes, 139

Orientation, 18, 87

Oversize diameters in drilling, 247

Paper gaging See Graphic analysis

Parallelism, 88

Partial runout, 179

Partial surface as a datum feature, 58

Pattern of features controlled to datums,

230 Pattern of features located to a second

Pattern of features, 236 Perpendicularity, 90

Perpendicularity refinement, 229

Pitch diameter rule, 36 Plug and Socket, 162 Position tolerance, 103, 125, 157 Position tolerance at MMC, 107 Profile, 18

Profile of a conical feature, 194 Projected tolerance zone, 28, 131 Radius, 27

Radius refinement with profile, 190 Radius symbol (R), 27

Reference dimension, 29 Regardless of feature size (RFS), 32, 35, 54, 106

Restrained condition, 79 Resultant condition, 32, 113 Rule #1, 33

Rule #2, 35 Rules, fundamental drawing, 10 Runout, 18, 177

Screw sizes, 248 Shift tolerance, 55, 109 Shift tolerance, special case, 142, 159 Size feature, 31

Size feature located to specified datums, 225

Size features located to a size feature, 231 Slope, 29

Specifying profile of a surface, 188 Spherical diameter (SØ), 28 Spherical radius (SR), 28 Spotface, 27

Square symbol, 28 Statistical tolerance, 28 Straightness of a median line and median plane, 74

Straightness of a surface, 72 Symbols used with geometric tolerancing, 25

Symmetrical features at MMC, 142 Tangent plane, 28, 91

Theoretical tolerance zone, 104 Tolerance

Angular, 13 Linear, 12 Tolerance zone overlay gage, 211, 215

Total runout, 178 True position, 32, 104 Two single-segment feature control frames, 138

Index 255

Two single-segment profile control,

198

Types of dimensions, 11

Virtual condition, 32

Virtual condition boundary, 110

Virtual condition rule, 36, 110

Worst-case boundary, 33 Zero dimensions, 157 Zero positional tolerance at maximum material condition, 115

Zero positional tolerance for a pattern of features, 233

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ABOUT THE AUTHOR

Gene R Cogorno has more than 25 years of experience as an educator and technical trainer He spent 12 years developing and instructing a practical training program in industrial education, and taught machine technology at San Jose State University for 3 years Mr Cogorno joined FMC Corporation as a Senior Technical Trainer in

1984 and founded Technical Training Consultants in 1992 He earned his bachelor’s and master’s degrees in Industrial Education from San Jose State University.

Copyright © 2006 by Gene R Cogorno Click here for terms of use.