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Objectives Understand description and control of variability through tolerancing Understand various classes of fits Introduce multiple part tolerancing 2

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Tolerance Tolerance is the total amount a dimension may vary. It is the difference between the maximum and minimum limits. Ways to Express: 1.Direct limits or as tolerance limits applied to a dimension 2.Geometric tolerances 3.A general tolerance note in title block 4.Notes referring to specific conditions 3

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ANSI/ASME Standard ANSI/ASME Standard Y14.5 Each dimension shall have a tolerance, except those dimensions specifically identified as reference, maximum, minimum, or stock. The tolerance may be applied directly to the dimension or indicated by a general note located in the title block of the drawing.

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1. Direct Limits and Tolerance Values 5

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1. Direct Limits and Tolerance Values Plus and Minus Dimensions 6

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2. Geometric Tolerance System AU 20087 Geometric Dimensioning and Tolerancing (GD&T) is a method of defining parts based on how they function, using standard ANSI symbols. Feature Control Frame Concentricity Symbol

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3. Tolerance Specifications in Title Block AU 20088 General tolerance note specifies the tolerance for all unspecified toleranced dimensions.

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Basic Hole System Clearance = Hole Shaft Cmax = Hmax Smin Cmin = Hmin Smax Both Cmax and Cmin 0 _________ fit Cmax > 0; Cmin < 0 ___________ fit What types of fits are these? AU 200820 S MAX S MIN H MAX H MIN

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Basic Hole System Clearance = Hole Shaft Cmax = Hmax Smin Cmin = Hmin Smax Both Cmax and Cmin 0 Clearance fit Cmax > 0; Cmin < 0 Transition fit System Tolerance = Cmax Cmin Allowance = Min. Clearance = Cmin AU 200821 S MAX S MIN H MAX H MIN

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Basic Hole System AU 200822.490.485.510.505 Calculate Maximum and Minimum Clearance Clearance = Hole Shaft Cmax = Hmax Smin Cmax =.510 .485 =.025 Cmin =.505 .490 =.015 What type of fit is this?Cmax > Cmin > 0 Clearance Cmin = Hmin Smax

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Metric Limits and Fits Based on Standard Basic Sizes ISO Standard Note that in the Metric system: Nominal Size = Basic Size Example: If the nominal size is 8, then the basic size is 8 23

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Metric Preferred Hole Basis System of Fits AU 200824

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Metric Tolerance Homework TOL-1 AU 200825 ???? 9.960 9.924 Free Running H9/d9 Basic Size: 10 (1) Nominal Size: ?(1) Nominal Size: 10 (2) Shaft Limits: (7) Minimum Clearance: ???? (8) Maximum Clearance: ???? (3) Shaft Tolerance: ????(3) Shaft Tolerance: 0.036 (4) Hole Limits: ???? 10.036 10.000 (5) Hole Tolerance: ????(5) Hole Tolerance: 0.036 (6) Ts: ????(6) Ts: 0.072 (7) Minimum Clearance: 0.040 (8) Maximum Clearance: 0.112 CHECK: Ts = Cmax Cmin?CHECK: 0.072 = 0.112 0.040 = 0.072

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Today's Assignment AU 200826