Practical Applications and Calculation Methods

12Practical Applications and

Calculation Methods

GD&T: Application and Interpretation © Goodheart-Willcox Co., Inc.

• Calculate position tolerances when more than two parts are stacked in a floating fastener or fixed fastener application.

• Distribute the total available position tolerance between features to which position tolerances are applied.

• Specify projected tolerance zones for fixed feature locations to prevent interference conditions.

• Determine the amount of tolerance accumulation in a simple assembly.

• Properly use zero position tolerances at MMC to increase manufacturing freedom.

• Apply paper gaging techniques to determine if a produced part meets drawing requirements.

Floating Fastener Condition—Two Stacked Parts

Floating Fastener Condition—Three Stacked Parts

Floating Fastener Condition— Two Hole Sizes & Distributed Tolerances

Fixed Fastener Condition—Two Stacked Parts

Fixed Fastener Condition—Two Parts, Unevenly Distributed Tolerances

Fixed Fastener Condition—Projected Tolerance Zone

Zero Position Tolerance at MMC

• Zero tolerancing at MMC increases manufacturing freedom

• Clearance conditions must exist• Located feature must have a size tolerance• Lets the manufacturer choose how to allocate

the tolerances

Zero Position Tolerance at MMC Application

Paper Gaging Techniques

• Measure hole locations relative to datum reference frame

• Calculate coordinate variations• Calculate diameter position variations• Plot coordinate variation values

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