GD&T Tips

Datum Feature Control

Primary Datum Surface Control - 1994, 2009 & 2018

Tie your datum features together - 1994

Keep It Simple

Example

With General Tolerance

Tie your datum features together - 2009 & 2018

Datum Feature Selection

Function Example

Slot as Primary

Application - Video!

Two Holes

Horizontal - Video!

On a Diagonal - Video!

Datum Feature Types

Primary

Linear Extrusion - Video!

Complex - Video!

Hole and Slot - Video!

Hole and Slot Simulation - Video!

Secondary

Watch the Placement of Datum Identification Symbols... 1994 & 2018

Watch the Placement of Datum Identification Symbols... 2009

Datum Features

Must Be Referenced - Video!

Axis vs. Center Line - Video!

Datum Not on Part - Video!

Datum Reference Frame

Oblique Angle

Establishing

Does a Datum Reference Frame Need to be Fully Constrained?

Displacement (Shift)

Tolerances Do Not Change

Rotational Shift - Video!

Geometry Effect - Video!

Example - Video!

Application - Video!

Datum features can give you a shift-not a bonus - 1994

Datum features can give you a shift-not a bonus - 2009, 2018

Exact Constraint

Over Constraint

Rocking Datum Feature - Video!

Orienting Datum Planes

Tertiary Datum Feature

Using a Slot - Video!

Sufficient Size

Short Hole - Video!

Datums must be of sufficient size!

Symbol Placement

Watch placement of datum triangles in the latest Standard - 1994, 2009, 2018

Watch where you put that triangle!

Basic and +/- Don’t Mix - Video!

+/- vs. Profile Example - Video!

Dimensioning vs. Tolerancing - Video!

Multiple In-Line Features - Video!

Implied - Video!

Slots - Video!

Reduced Dimension Drawings

Rounding

Converting

Schedule of Tolerances

Basic

Do Not Tolerance

Toleranced Dimensions

Don’t Mix Dimensioning

General Notes

Trailing Zeros

Half Dimensions - Video!

Angles

Compound Angle - Video!

When it Comes to Dimensions: “Give the Customer What they Need”!

Placement

Get Back to Datums

And Composite - Video!

Basic Dimension Placement Doesn’t Matter - Video!

Give Production the Dimensions They Need - 1994, 2009, 2018

Direct Tolerancing

Time to Stop the Nonsense - 1994, 2009 & 2018

Don’t Located With +/- - Video!

Tolerance Zone Shape - Video!

Continuous Feature - Video!

Interrupted - Video!

Determining - Video!

Locating Dimensions to Centers

Irregular Features of Size - Video!

Envelopes

Determining Size and Center - Video!

Irregular Features of Size

Locate with Profile

Locate with Position

Inspecting at MMC - Video!

Center Plane Control - Video!

When Using “Unit Basis”, Include an Overall Limit!

Never a Datum Reference

Drawing Previews - Video!

Selecting Controls - Video!

Pyramid

Profile

Features of Size

Simulating a Hard Gage

CMM Simulating Gage

Uncertainty

Measurement versus Verification - Video!

Notes

An Individual Tolerance - Video!

Never Locate

Say What You Mean - Video!

When to Use It - Video!

Stabilizing the Zone - Video!

Extension of Principle - Video!

Threads at MMC

Formulas

Put Your Holes at Any Angle!

Locating Features of Size

Calculating Bonus - 1994

Bi-directional Control

Boundary Control

MMC and LMC Are Single Limits

Calculating Bonus - 2009 and 2018

Think Boundary, not Bonus - 1994, 2009, 2018

Composite

Datum Feature References

Second Segment

Using a Note - Video!

Several Examples - Video!

Feature to Feature Control - Video!

Composite l - Video!

Composite ll - Video!

Composite lll - Video!

Composite l Gage - Video!

Composite ll Gage - Video!

Composite lll Gage - Video!

Single Segment

Example l

Composite Vs Single Segment - 1994, 2009, 2018

Cpk Calculation

Coaxial Example

From CMM Data

Placement - Video!

At MMC - Video!

Calculating Size Tolerance

Tolerance on Two Surfaces

Of a Line

Controlling Size Part l

Controlling Size Part ll

Unequal and Unilateral

The most important control in GD&T is location, location, location - 1994, 2009, 2018

Protect your boundaries with Profile - 1994, 2009, 2018

Controlling Size and Form

Unit Basis - Video!

Between - Video!

Use Profile to Control Size and Form - Video!

Applications

Cutter Ring

Irregular Feature

As a General Tolerance

Simplify Your GD&T - 1994 & 2009

Profile can Control Location of Irregular Features - Video!

Simplify Your GD&T - 2018

Composite

On a Single Surface

Position can Control Location of Irregular Features - Video!

Coplanarity

For Coplanarity use Profile - 1994

And Parallelism

For Coplanarity Use Profile - 2009 & 2018

Inspection

Simplified Inspection

Reporting ll - Video!

Remember, inspection is work versus risk!

What Are The Rules? 1994, 2009 & 2018

Defaults - Video!

Rule #1

Inspection - 1994, 2009, 2018

Size Controlling Form - 1994, 2009, 2018

Is Not an Option

Break the Rule - Video!

Simultaneous Requirements

Creating a Pattern

Simplifying the Dimensions - Video!

Application - Video!

If you don’t want a pattern, you have to say so!

Keep Your Runouts Straight

Keep your Runouts Straight!

When in Doubt - Use Runout - 1994 and 2009

Don’t give runout more credit than it deserves - 1994, 2009, 2018

When in Doubt, use Runout! - 2018

Molded Part Symbols - Video!

Default Tolerances - Video!

Difference in Revisions - Video!

Y14.41 - Video!

Other Standards - Video!

2009 Symbols - Video!

Are Voluntary - Video!

Addendum - Video!

2009 Revision - Video!

Matter of Life or Death - Video!

Get Up to Speed with the ASME Y14.5-2018 Edition - 2018

Consider straightness on your parts made from flat stock - 1994

Consider Runout

Two Kinds of Straightness Tolerance - 1994

Center Plane at MMC - Indicator Inspection

Two Kinds of Straightness Tolerance - 2009 and 2018

Consider flatness at MMC on your parts made from flat stock - 2009 & 2018

Use Position - 1994

Use Position - 2009

Use Position - 2018

Projected Tolerance - 1994 and 2009

Projected Tolerance - 2018

Free State

Restraint with Datum Targets - Video!

Use the Free State Symbol for your Flexible Parts - 1994, 2009, 2018

Tangent Plane

Application

No Form Control

GD&T and Engineering Resources

GD&T Tips and Symbols

Online GD&T Quiz

Most Recent GD&T Tips:

When it Comes to Dimensions: “Give the Customer What they Need”!

When Using “Unit Basis”, Include an Overall Limit!

Put Your Holes at Any Angle!

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GD&T and Engineering Resources

GD&T Tips and Symbols

Online GD&T Quiz

GD&T Tips

Most Recent GD&T Tips:

When it Comes to Dimensions: “Give the Customer What they Need”!

When Using “Unit Basis”, Include an Overall Limit!

Put Your Holes at Any Angle!

Select the Tip category below to view Tips. Tips in Red are available on-line for free. Tips with a video has "Video" next to the title. For access to all Tips, including PDFs, become a member of our Premium site. Only $19.95/year Tips only or $49.95/year for full access. Join Today!

Register to Receive Updated GD&T Tips in Your Email Box

Select the Tip category below to view Tips. Tips in Red are available on-line for free. Tips with a video has "Video" next to the title.

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