Geometric Dimensioning and Tolerancing (GD&T)

Define the fundamental rule e: drawings define a part without specifying manufacturing methods, and tolerance drives the manufacturing process from milling to finishing.

Rule l requires measuring all dimensions and tolerances at 20°C unless stated otherwise, because temperature changes affect diameter and length, necessitating compensation when 20°C measurement isn't possible.

Explore the regular feature of size across cylindrical, spherical, and circular elements with opposing parallel surfaces. Use vernier calipers to identify internal and external features versus non feature of size.

Explore geometric dimensioning and tolerancing by identifying regular and irregular features of size, type a and type b, with labeled surfaces, dimensions, and envelope.

Learn how the feature control frame, a box with two to five compartments, uses a geometric symbol and a tolerance value with modifiers and datums to control features on drawings.

Assess straightness with a dial indicator on a surface plate, distinguishing straightness error from taper error via full indicator movement, verified by a slip gauge or gauge wire.

Apply circularity verification techniques in GD&T using a dial indicator and rotation to measure circularity error across cross sections, and compare graph sheet plotting with computer-based plots.

Identify how datum reference frames establish primary, secondary, and tertiary datums to arrest all six degrees of freedom and serve as the measurement origin in GD&T.

Define the width datum as the center plane of a prismatic part, arresting one translation and two rotations with a datum feature simulator and illustrating with datum symbols.

Explore axis datum in gd&t, detailing datum feature symbols and extension lines, and illustrate how a collet fixes the axis to arrest four degrees of freedom.

Shows how a complex feature can serve as a primary datum, with three planes forming the datum reference frame and the datum feature simulator arresting all six degrees of freedom.

Explore datum targets in GD&T, including points, lines, and areas, and learn how the datum target identification symbol encodes their position. Apply the 3-to-1 principle and movable datum targets.

Control angularity of center plane, a feature of size, to 60 degrees relative to datum, within parallel planes 0.2 apart, using maximum and least material condition modifiers for bonus tolerance.

Demonstrates applying angularity to a hole axis within a 0.2 cylindrical tolerance zone, enabling axis variation around 60 degrees and using material condition modifiers for added flexibility.

Learn parallelism control in GD&T by the center plane of a slot referenced to datum E, kept between two parallel planes 0.2 M apart with the maximum material condition modifier.

Discover how the ASME 14.5 2009 alternate practice replaces perpendicularity and parallelism with angularity for orientation control, clarifying datum relations and applying angularity to any angle.

Convert coordinate dimensions to a basic dimension, apply a position tolerance with a datum framework, and establish a cylindrical tolerance zone (1.4 diameter) for hole location and orientation.

Demonstrate applying total runout and radial runout on axisymmetric parts and faces to control cylindricity and flatness, using datum B as primary and A as secondary to guide orientation.

Illustrates profile unilateral outside in GD&T, with lower size 60 and upper limit 60.4 within a 0.4 boundary referenced to datum A and B. It shows adding material, not removing.

Define the profile of a line as a GD&T symbol where the profile line lies between two parallel boundaries 0.2 m apart, governing form, orientation, and location.