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Dimensioning and Tolerancing

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Title: Slide 1 Author: David P. Madsen Last modified by: jeggemeyer Created Date: 11/17/2010 10:27:31 PM Document presentation format: On-screen Show (4:3) – PowerPoint PPT presentation

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Title: Dimensioning and Tolerancing


1
CHAPTER 10
  • Dimensioning and Tolerancing

2
Learning Objectives
  • Identify and use common dimensioning systems
  • Explain and apply dimensioning standards based on
    ASME Y14.5-2009
  • Apply proper specific notes for manufacturing
    features
  • Place proper general notes and flag notes on a
    drawing
  • Interpret and use correct tolerancing techniques

3
Learning Objectives
  • Prepare completely dimensioned multiview drawings
    from engineering sketches and industrial drawings
  • Apply draft angles as needed to a drawing
  • Dimension CAD/CAM machine tool drawings
  • Prepare casting and forging drawings

4
Learning Objectives
  • Provide surface finish symbols on drawings
  • Solve tolerance problems including limits and
    fits
  • Use an engineering problem as the basis for your
    layout techniques
  • Describe the purpose of ISO 9000 Quality Systems
    Standard and related standards

5
Dimensions
  • Required on detail drawings
  • Provide shape and size description
  • Size dimensions
  • Location dimensions
  • Notes
  • Local notes (specific notes)
  • General notes

6
Dimensions
7
ASME Dimensioning Standards
  • ASME Y14.5, Dimensioning and Tolerancing
  • General note DIMENSIONING AND TOLERANCING PER
    ASME Y14.5-2009
  • Several other ASME documents with standards
    related to dimensioning and tolerancing

8
Dimensioning Definitions
  • Actual size
  • Allowance
  • Basic dimension
  • Bilateral tolerance
  • Datum
  • Diameter
  • Feature
  • Feature of size
  • Geometric tolerance
  • Least material condition (LMC)
  • Limits of dimension

9
Dimensioning Definitions
  • Maximum material condition (MMC)
  • Nominal size
  • Radius
  • Reference dimension
  • Stock size
  • Specified dimension
  • Tolerance
  • Unilateral tolerance

10
Fundamental ASME Y14.5 Dimensioning Rules
  • Each dimension has a tolerance except reference,
    maximum, minimum, or stock
  • Dimensioning and tolerancing must be complete
  • Show each necessary dimension of an end product
  • Select and arrange dimensions to suit the
    function and mating relationship of a part

11
Fundamental ASME Y14.5 Dimensioning Rules
  • Dimensions must not be subject to more than one
    interpretation
  • Do not specify the manufacturing processes unless
    necessary
  • Identify nonmandatory dimensions with an
    appropriate note
  • Arrange dimensions to provide required
    information and optimum readability
  • Show dimensions in true profile views and visible
    outlines

12
Fundamental ASME Y14.5 Dimensioning Rules
  • Dimension diameter or thickness of materials
    manufactured to gage or code numbers
  • 90angle is implied for centerlines and lines
  • 90basic angle is implied for centerlines located
    by basic dimensions
  • A zero basic dimension applies where axes, center
    planes, or surfaces are shown one over the other
    with established geometric controls

13
Fundamental ASME Y14.5 Dimensioning Rules
  • Unless otherwise specified, all
  • Dimensions and tolerances are measured at 20C
    (68F)
  • Dimensions and tolerances apply in a free state
    condition except for nonrigid parts
  • Tolerances apply for the full depth, length, and
    width of the feature
  • Dimensions and tolerances apply on the drawing
    where specified

14
Fundamental ASME Y14.5 Dimensioning Rules
  • Coordinate systems
  • Right-handed (arranged clockwise)
  • Labeled axes and positive direction shown
  • 3-D model complies with ASME Y14.41, Digital
    Product Definition Data Practices

15
Dimensioning Components
16
Dimensioning Symbols
17
Unidirectional Dimensioning
  • Numerals, figures, and notes lettered
    horizontally
  • Read from the bottom of the drawing sheet
  • Mechanical drafting for manufacturing

18
Aligned Dimensioning
  • Numerals, figures, and notes aligned with the
    dimension lines
  • Horizontal dimensions read from the bottom
  • Vertical dimensions read from the right side
  • Architectural and structural drafting
  • 0

19
Rectangular Coordinate Dimensioning without
Dimension Lines
  • Ordinate dimensioning
  • Dimension values aligned with extension lines
  • Dimension represents a measurement originating
    from datums or coordinates
  • Features such as holes sized using specific notes
    or a table
  • Popular for
  • Precision sheet metal part drawings
  • Electronics drafting

20
Rectangular Coordinate Dimensioning without
Dimension Lines
21
Tabular Dimensioning
  • Form of rectangular coordinate dimensioning
    without dimension lines
  • Features dimensioned in a table

22
Chart Dimensioning
  • Used when a part or assembly has one or more
    dimensions that change depending on the specific
    application

23
Millimeter Dimensions
  • Millimeters (mm)
  • Common International System of Units (SI) unit of
    measure
  • General note UNLESS OTHERWISE SPECIFIED, ALL
    DIMENSIONS ARE IN MILLIMETERS
  • Follow any inch dimensions with IN

24
Proper Use of Metric Units
  • Omit decimal point and 0 when dimension is a
    whole number
  • Precede a decimal value that is less than 1 with
    a 0
  • When the value is greater than a whole number by
    a fraction of a mm, do not place a 0 next to last
    digit
  • Exception when displaying tolerance values

25
Proper Use of Metric Units
  • Plus and minus tolerance values have same number
    of decimal places
  • Limit tolerance values have same number of
    decimal points
  • Unilateral tolerances use a single 0 without a
    corresponding or sign

26
Inch Dimensions
  • Decimal inches (IN)
  • United States (U.S.) customary unit of measure
  • General note UNLESS OTHERWISE SPECIFIED, ALL
    DIMENSIONS ARE IN INCHES
  • Follow any millimeter dimensions with mm

27
Proper Use of Inch Units
  • Do not precede a value that is less than 1 inch
    with a 0
  • Express a specified dimension to the same number
    of decimal places as its tolerance
  • Fractional inches generally indicate larger
    tolerance

28
Proper Use of Inch Units
  • Plus and minus tolerance values have the same
    number of decimal places
  • Unilateral tolerances use the and sign
  • The 0 value has the same number of decimal places
    as the value that is greater or less than 0
  • Limit tolerance values have the same number of
    decimal points

29
Proper Use of Angular Units
  • Use decimal or degreesminutesseconds format
  • Angle and tolerance values have the same number
    of decimal places
  • Include 0or 00? when specifying only minutes or
    seconds, as applicable

30
Using Fractions
  • Not as common as decimal inches or millimeters
  • Architectural and structural drawings
  • Generally indicate larger tolerance

31
Arrowheads
  • Terminate dimension lines and leaders
  • Three times as long as they are wide
  • Consistent size
  • Filled in solid or open

32
Dimension Line Spacing
  • First dimension line
  • Uniform distance from the object
  • .375 in. (10 mm) minimum
  • .5 - 1.0 in. (12 - 24 mm) preferred
  • Succeeding dimension lines
  • Equally spaced
  • .25 in. (6 mm) minimum
  • .5 - .75 in. (12 - 20 mm) preferred

33
Dimension Numerals
34
Chain Dimensioning
  • Creates tolerance stacking (tolerance buildup)
  • Omit one intermediate dimension or the overall
    dimension

35
Baseline Dimensioning
  • Size or location of features controlled from a
    common reference plane
  • Reduces possibility of tolerance stacking

36
Direct Dimensioning
  • Results in the least tolerance stacking

37
Dimensioning Symmetrical Objects
38
Dimensioning Cylinders
39
Dimensioning Square Features
40
Preferred Dimensioning Practices
  • Avoid crossing extension lines
  • Do not break extension lines when they cross
  • Never cross extension lines over dimension lines
  • Break the extension line where it crosses over a
    dimension line when necessary

41
Preferred Dimensioning Practices
  • Never break a dimension line
  • Break extension lines when they cross over or
    near an arrowhead
  • Avoid dimensioning over or through the object
  • Avoid dimensioning to hidden features

42
Preferred Dimensioning Practices
  • Avoid long extension lines
  • Avoid using any line of the object as an
    extension line
  • Dimension between views when possible
  • Group adjacent dimensions

43
Preferred Dimensioning Practices
  • Dimension to views that provide the best shape
    description
  • Do not use a centerline, extension line, phantom
    line, visible object line, or a continuation of
    any of these lines as a dimension line
  • Stagger adjacent dimension numerals so they do
    not line up

44
Dimensioning Angular Surfaces
45
Dimensioning Chamfers
46
Dimensioning Conical Shapes
47
Dimensioning Hexagons and Other Polygons
  • Dimension across the flats

48
Dimensioning Arc Radius
49
Dimensioning Arc Length
50
Additional Radius Dimensioning Applications
  • True radius
  • TRUE R followed by the actual radius
  • Controlled radius
  • CR followed by the radius
  • Spherical radius
  • SR followed by the radius

51
Dimensioning Contours Not Defined as Arcs
  • Dimension coordinates or points along the contour
    from common surfaces
  • Series of dimensions on the object and along the
    contour
  • Tabular dimensioning

52
Locating a Point Established by Extension Lines
53
Dimensioning Circles and Thru Holes
54
Dimensioning Blind Holes
55
Dimensioning a Counterbore
56
Dimensioning a Spotface
57
Countersink or Counterdrill
58
Dimensioning Multiple Features
  • Number of features, X, a space, feature
    specification
  • Dimension to one of the features only
  • Examples
  • 4X Ø6 THRU or 4X Ø6
  • 2X R.50
  • 3X 8X45

59
Dimensioning Slots
60
Dimensioning Keyseats and Keyways
61
Dimensioning Knurls
62
Dimensioning Necks and Grooves
63
Rectangular Coordinate Dimensioning
64
Polar Coordinate Dimensioning
65
Dimensioning Repetitive Features
66
Locating Multiple Tabs in a Polar Orientation
67
Locating Multiple Features of Nearly the Same Size
68
Specifying Dimension Origin
  • Clearly identifies from which feature the
    dimension originates

69
Dimensioning Auxiliary Views
70
General Notes and Specifications
  • Sheet blocks
  • Material
  • General tolerances
  • Scale
  • Part name
  • Sheet size
  • Part number
  • Number of revisions
  • Projection
  • Outside sheet blocks
  • Machining practices
  • Common dimensions
  • Finish or other treatments

71
Flag Notes
  • Delta note
  • Specific note placed with general notes
  • Keyed to the drawing
  • Delta symbol (?) common
  • Hexagons and circles also used

72
Tolerances
  • Help ensure parts fit together and function in an
    assembly
  • Apply to all dimensions on a drawing, except
  • Reference
  • Maximum
  • Minimum
  • Stock size

73
Plus-Minus Dimensioning
  • Calculate the upper and lower limits from the
    specified dimension and plus-minus tolerance
  • Bilateral tolerance
  • Most common tolerancing method
  • Equal bilateral tolerance
  • Insert 6.5 ? 0.2, match to unequal bilateral
    tolerance style
  • Often preferred by manufactures
  • Unequal bilateral tolerance
  • Insert

74
Unilateral Tolerance
  • Insert , match to unequal bilateral
    tolerance style
  • Used by some companies to define fits between
    mating parts
  • Often avoided by CNC machine programmers

75
Limit Dimensioning
  • Calculate the tolerance from the upper and lower
    limits
  • Common for defining fits between mating parts
  • Preferred by some companies or departments

76
Single Limits
  • Can be used for common machine processes
  • Follow dimension value with (MIN) or (MAX)
  • Design determines unspecified limit

77
Specified and Unspecified Inch Tolerances
78
Specified and Unspecified Metric Tolerances
  • ISO 2768 classes of size tolerances
  • Fine (f)
  • Medium (m)
  • Coarse (c)
  • Very coarse (v)

79
Applying Statistical Tolerancing
80
Maximum Material Condition (MMC)
  • External feature is at MMC at its largest limit
  • Internal feature is at MMC at its smallest limit

81
Least Material Condition (LMC)
  • External feature is at LMC at its smallest limit
  • Internal feature is at LMC at its largest limit

82
Clearance Fit
83
Allowance
MMC Internal Feature
MMC External Feature
Allowance
84
Interference Fit
  • Force or shrink fit
  • Examples
  • Bushing pressed onto a housing
  • Pin is pressed into a hole

85
Extreme Form Variation
  • Established by limits of size
  • Specified by Rule 1 in ASME Y14.5

86
Limits and Fits Between Mating Parts
  • Fit determined first based on the use or service
  • Limits of size established second to ensure the
    desired fit
  • ANSI/ASME B4.1 Preferred Limits and Fits for
    Cylindrical Parts
  • ANSI/ASME B4.2 Preferred Metric Limits and Fits
  • Tables of establishing dimensions for standard
    ANSI fits

87
Running and Sliding Fits (RFC)
  • RC1Close sliding fits
  • RC2Sliding fits
  • RC3Precision running fits
  • RC4Close running fits
  • RC5 and RC6Medium running fits
  • RC7Free running fits
  • RC8 and RC9Loose running fits

88
Locational Fits (LC, LT, LN)
  • LCLocational clearance fits
  • LTLocational transition fits
  • LNLocational interference fits

89
Force Fits (FN)
  • FN1Light drive fits
  • FN2Medium drive fits
  • FN3Heavy drive fits
  • FN4 and FN5Force fits

90
Dimensions Applied to Platings and Coatings
  • General note
  • DIMENSIONAL LIMITS APPLY BEFORE (AFTER) PLATING
    (COATING)
  • Specific note
  • Leader with a dot pointing to the specific
    surface instead of an arrowhead

91
Casting Drawing and Design
  • Depends on
  • Casting process and characteristics
  • Material
  • Design or shape of the part
  • Die or mold
  • Based on ASME Y14.8, Castings and Forgings
    standard

92
Shrinkage Allowance
  • Extra material to account for cooling
  • Examples
  • Iron .125 in. per ft. (.4 mm per meter)
  • Steel .250 in. per ft.
  • Aluminum .125 to .156 in. per ft. (.4 mm.5 per
    meter)
  • Brass .22 in. per ft. (.7 mm per meter)
  • Bronze .156 in. per ft. (.5 mm per meter)
  • Patternmaker applies shrink rules

93
Draft
  • Not necessary on horizontal surfaces
  • Begin at the parting line and parting plane
  • Tapers away from the molding material

94
Draft on a Drawing
  • General note
  • ALL DRAFT ANGLES .010
  • ALL DRAFT ANGLES 6
  • Angular dimensions
  • Plus draft and/or minus draft methods

95
Parting Lines on a Drawing
96
Fillets and Rounds in Casting
  • Allow the pattern to eject freely from the mold
  • Fillets help reduce the tendency of cracks to
    develop during shrinkage
  • Radii determined by part thickness

97
Machining Allowance
  • Extra material for any surface to be machined
  • Examples
  • Iron and steel .125 in. (3 mm)
  • Brass, bronze, and aluminum .062 in. (1.5 mm)
  • Greater for large castings or those with a
    tendency to warp

98
Casting Drawings
  • Casting drawing
  • Machining drawing
  • Combined casting and machining drawing
  • Drawing phantom lines to show machining allowance
    and draft angles

99
Forging Design and Drawing
  • Focuses on dies
  • Draft
  • Fillets and rounds
  • Machining allowance
  • Based on ASME Y14.8, Castings and Forgings
    standard

100
Forging Drawings
  • Stock material drawings
  • Show size and shape of the stock material
  • Outline of the end product using phantom lines
  • Detail drawings
  • Show the end product
  • Usually show draft
  • Use phantom lines to show machining allowance and
    draft angles

101
Surface Finish (Surface Texture)
  • Obtained by
  • Machining
  • Grinding
  • Honing
  • Lapping
  • Specified using surface finish symbol

102
Surface Finish Characteristics
  • Roughness
  • Waviness
  • Lay
  • Flaws

103
Surface Finish Symbol
104
Design and Drafting of Machined Features
  • Capabilities of the machinery available
  • Least-expensive method to get the desired result
  • Avoid over-machining

105
Tool Design
  • Jig and fixture design
  • Machining operations require special tools to
    hold the workpiece or guide the machine tool
  • Involves knowledge of
  • Kinematics
  • Machining operations
  • Machine tool function
  • Material handling
  • Material characteristics

106
Jig and Fixture Drawings
  • Assembly drawing with all components of the tool
  • Fast-acting clamps
  • Spring-loaded positioners
  • Clamp straps
  • Quick-release locating pins
  • Handles
  • Knobs

107
Jig and Fixture Drawings
108
Tools in Manufacturing
  • Drill jigs
  • Datums
  • Drill fixtures
  • Machining fixtures
  • Welding fixtures
  • Inspection fixtures
  • Progressive dies

109
Qualities of Tools
  • Reliability
  • Repeatability
  • Ease of use
  • Ease of manufacture
  • Ease of maintenance and repair

110
Basic Elements of Tool Design
  1. Visualizing how shop personnel will accomplish a
    specific task
  2. Conceptualizing hardware to assist in the
    accomplishment of that task
  3. Creating drawings so the hardware can be
    manufactured

111
Introduction to ISO 9000
  • ISO 9000-1
  • Direction and definitions that describe what each
    standard contains
  • Assists companies in the selection and use of the
    appropriate ISO standard
  • ISO 9001
  • Model for designing, documenting, and
    implementing ISO standards
  • ISO 9002
  • ISO 9001 but does not contain the requirement of
    documenting the design and development process

112
Introduction to ISO 9000
  • ISO 9003
  • Companies or organizations that only need to
    demonstrate through inspection and testing
    methods that they are providing the desired
    product or service
  • ISO 9004-1
  • Set of guidelines for development and
    implementation of a quality management system

113
Glossary
  • Actual size
  • The measured size of a feature or part after
    manufacturing.
  • Allowance
  • The tightest possible fit between two mating
    parts.
  • Allowance
  • The tightest possible fit between two mating
    parts.

114
Glossary
  • Baseline dimensioning
  • A common method of dimensioning machine parts
    whereby each feature dimension originates from a
    common surface, axis, or center plane.
  • Basic dimension
  • A theoretically exact size, location, profile, or
    orientation of a feature or point.
  • Bilateral tolerance
  • A tolerance allowed to vary in two directions
    from the specified dimension.

115
Glossary
  • Bilateral tolerance
  • A tolerance in which variation is permitted in
    both directions from the specified dimension.
  • Blind hole
  • A hole that does not go through.
  • Casting
  • An object or part produced by pouring molten
    metal into a mold.

116
Glossary
  • Chain dimensioning
  • Also known as point-to-point dimensioning, a
    method of dimensioning from one feature to the
    next.
  • Chamfer
  • A slight surface angle used to relieve a sharp
    corner.
  • Clearance fit
  • A condition when, due to the limits of
    dimensions, there is always a clearance between
    mating parts.

117
Glossary
  • Controlled radius
  • The limits of the radius tolerance zone must be
    tangent to the adjacent surfaces, and there can
    be no reversals in the contour.
  • Counterbore
  • Often used to machine a diameter below the
    surface of a part so a bolt head or other
    fastener can be recessed.
  • Counterdrill
  • A combination of two drilled features.

118
Glossary
  • Countersink
  • A conical feature in the end of a machined hole.
  • Datum
  • A theoretically exact surface, plane, axis,
    center plane, or point from which dimensions for
    related features are established.
  • Delta
  • A triangle symbol (?) placed on the drawing for
    reference.

119
Glossary
  • Diameter
  • The distance across a circle measured through the
    center.
  • Die
  • Any device used to produce a desired shape, form
    or finish to a material.
  • Dimension
  • A numerical value or values, or mathematical
    expression provided in appropriate units of
    measure and used to define form, size,
    orientation or location of a feature or part.

120
Glossary
  • Direct dimensioning
  • Dimensioning applied to control the size or
    location of one or more specific features.
  • Draft
  • The taper allowance on all vertical surfaces of a
    pattern, which is necessary to facilitate the
    removal of the pattern from the mold.
  • Equal bilateral tolerance
  • A tolerance where the variation from the
    specified dimension is the same in both the and
    directions.

121
Glossary
  • Extreme form variation
  • The variation of the form of the feature between
    the upper limit and lower limit of a size
    dimension.
  • Feature of size
  • One cylindrical or spherical surface, a circular
    element, or a set of two opposed elements or
    opposed parallel plane surfaces, each of which is
    associated with a directly toleranced dimension.
  • Feature
  • The general term applied to describe a physical
    portion of a part or object, such as a surface,
    slot, tab, pin, keyseat, or hole.

122
Glossary
  • Forging
  • A process of shaping malleable metals by
    hammering or pressing between dies that duplicate
    the desired shape.
  • Free state condition
  • Distortion of the part after removal of forces
    applied during manufacturing.
  • General notes
  • Information that relates to the entire drawing.

123
Glossary
  • General notes
  • Notes placed separate from the views and relate
    to the entire drawing.
  • Geometric tolerance
  • The general term applied to the category of
    tolerances used to control size, form, profile,
    orientation, location, and runout.
  • Interference fit
  • The condition that exists when, due to the limits
    of the dimensions, mating parts must be pressed
    together.

124
Glossary
  • Keyseat
  • A groove or channel cut in a shaft.
  • Keyway
  • A shaft and key are inserted into a hub, wheel,
    or pulley where the key mates with a groove
    called a keyway.
  • Kinematics
  • The study of mechanisms.

125
Glossary
  • Knurling
  • A cold forming process used to form a cylindrical
    or flat surface uniformly with a diamond or
    straight pattern creating a knurl.
  • Lay
  • The direction or configuration of the predominant
    surface pattern.
  • Least material condition (LMC)
  • The condition where a feature contains the least
    amount of material allowed by the size limits.

126
Glossary
  • Least material condition (LMC)
  • The opposite of MMC, the least amount of material
    possible in the size of a feature within the
    stated limits.
  • Limit dimensioning
  • A system of dimensioning where the upper and
    lower limits of the tolerance are provided and
    there is no specified dimension given.
  • Limits of dimension
  • The largest and smallest possible boundary to
    which a feature can be made as related to the
    tolerance of the dimension.

127
Glossary
  • Limits of size
  • The amount of variation in size and geometric
    form of a feature control. The boundary between
    maximum material condition (MMC) and least
    material condition (LMC).
  • Local notes (specific notes)
  • Notes connected to specific features on the views
    of the drawing.
  • Location dimensions
  • Dimensions that provide the relationship of
    features of an object.

128
Glossary
  • Locational fits (LC, LT, LN)
  • Provide rigid or accurate location, as with
    interference fits, or provide some freedom of
    location, as with clearance fits.
  • Maximum material condition (MMC)
  • The condition of a part or feature when it
    contains the most amount of material within the
    stated limits.

129
Glossary
  • Mold
  • A form made to pour or inject material to produce
    the desired shape.
  • Neck
  • The result of a machining operation that
    establishes a narrow groove on a cylindrical part
    or object.
  • Nominal size
  • A dimension used for general identification such
    as stock size or thread diameter.

130
Glossary
  • Nonrigid parts
  • Parts that can have dimensional change due to
    thin wall characteristics.
  • Notes
  • A type of dimension that generally identify the
    size of a feature or features with written
    specifications that are more detailed than a
    numerical value.
  • Parting line
  • The separation between the mold or die
    components, and is a line on the drawing
    representing the mating surfaces between the mold
    or die components.

131
Glossary
  • Parting plane
  • The mating surfaces of a die or mold.
  • Patternmaker
  • A person who makes a pattern for casting and
    forging applications.
  • Plus-minus dimensioning
  • A system of dimensioning that provides a nominal
    dimension and an amount of allowable variance
    from that dimension.

132
Glossary
  • Polar coordinate dimensioning
  • Using angular dimensions to locate features from
    planes or centerlines.
  • Radius
  • The distance from the center of a circle to the
    outside.
  • Rectangular coordinate dimensioning
  • Using linear dimensions to locate features from
    planes or centerlines.

133
Glossary
  • Reference dimension
  • A dimension used for information purposes only
    and is usually without a tolerance.
  • Running and sliding fits (RFC)
  • Intended to provide a similar running performance
    with suitable lubrication allowance throughout
    their range of sizes.
  • Single limits
  • Used when the specified dimension cannot be any
    more than the maximum or less than the minimum
    given value.

134
Glossary
  • Size dimensions
  • Dimensions placed directly on a feature to
    identify a specific size or may be connected to a
    feature in the form of a note.
  • Specifications
  • Any written information or instructions included
    on the drawing or with a set of drawings, giving
    all necessary information not shown in the
    drawing field.
  • Specified dimension
  • The part of the dimension from which the limits
    are calculated.

135
Glossary
  • Spotface
  • Provides a flat bearing surface for a washer face
    or bolt head.
  • Statistical tolerancing
  • The assigning of tolerances to related dimensions
    in an assembly based on the requirements of
    statistical process control (SPC).
  • Stock size
  • A commercial or pre-manufactured size, such as a
    particular size of square, round, or hex steel
    bar.

136
Glossary
  • Surface finish (surface texture)
  • The roughness, waviness, lay, and flaws of a
    surface.
  • Surface roughness
  • Fine irregularities in the surface finish and is
    a result of the manufacturing process used.
  • Surface waviness
  • The often widely spaced condition of surface
    texture usually caused by such factors as machine
    chatter, vibrations, work deflection, warpage, or
    heat treatment

137
Glossary
  • Tolerance stacking (tolerance buildup)
  • The tolerance of each dimension builds on the
    next.
  • Tolerance
  • The total permissible variation in size or
    location.
  • True radius
  • The actual radius of an arc even though it may be
    shown not true size and shape.

138
Glossary
  • Unequal bilateral tolerance
  • A tolerance where the variation from the
    specified dimension is not the same in both
    directions.
  • Unilateral tolerance
  • A tolerance where the variation is permitted to
    increase or decrease in only one direction from
    the specified dimension.
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