In this Question Line video, Jason walks through an assembly drawing to explain the scenario where a feature being controlled by position must have a reference size dimension rather than a tolerance on the size of the feature.
In this Question Line video, Jason discusses a composite feature control frame controlling profile tolerance. He walks through through the user submitted examples to explain the controls of each frame.
In this Question Line video, Jason responds to a question regarding radial hole patterns as datum features. He discusses how to set up the datum reference frame, how the datum reference frame controls degrees of freedom, and how to apply the Maximum Material Boundary.
In this Question Line video, Jason reviews cylindricity and discusses how it is measured.
In this Question Line Video, Jason gives a high-level overview of how polar probes and TIR checkers are used to inspect circularity or cylindricity.
In this question line video, Jason explains how to control radial position with a composite tolerance by walking through an example of a pattern of holes on a cylinder.
Jason walks through an example showing how to inspect a hole with position at an angle, rather than parallel or perpendicular, to the primary datum.
In this video, Jason explains how to use a Multiple Single Segment feature control frame to achieve bidirectional position control.
Jason walks through the potential issues associated with using V-Blocks and how they can affect measurements of circularity and runout.
Coordinate Measuring Machines (CMMs) are essential tools for obtaining precise measurements. However, to ensure accurate measurements, it is crucial to understand how to use them correctly. In this video, Jason explains the importance of recognizing and utilizing appropriate vectors when inspecting a profile or irregular surface with a CMM probe.
This series explores common errors in implementing GD&T on engineering drawings and provides practical solutions to avoiding them.
Geometric Dimensioning and Tolerancing, and the concept of “True Position,” originated due to a rejection of functional parts as a result of coordinate dimensioning. Let’s look at a simple assembly to illustrate why this is true, and how GD&T Position takes care of this problem.
Address the skills gap in manufacturing with training programs that build GD&T knowledge, improve drawing interpretation, and support effective inspection.
In this Question Line video, Brandon explains how a go gage and no-go gage are used to verify that Rule #1 of GD&T is met for a feature of size.
As our Training Design Engineer at GD&T Basics, Jason Richter is responsible for creating and maintaining lessons and visual content for our courses and YouTube page, as well as hosting our GD&T Public Training Seminars.
Jason discusses how to select the appropriate datum feature when designing a hollow cylindrical part where both the ID and OD are mating features.
Jason discusses form controls on a per unit basis using the example of controlling flatness on a large surface in this Question Line Video.
Jason walks through drawing examples to explain how to tell at a glance whether a drawing is using inch or metric dimensions.
In this Question Line video, Jason compares the use of functional gages and CMMs for inspection and discusses benefits and drawbacks of each.
Jason answers a student’s question regarding whether a feature of size can be designed to both MMC and LMC boundary constraints.
In this Question Line Video, Jason uses the example of a cylindrical datum feature to show how non-planar datums can be simulated and how they are able to constrain degrees of freedom.
In this Question Line Video, Jason reviews a drawing example and compares the ASME and ISO standards for controlling a hole with position tolerance.
"Why isn’t Maximum Material Condition always just the largest size the feature can be?” Jason answers our student's question and gives us a delicious way to remember the MMC state in this Question Line Video.
Jason reviews a drawing with two identical cutouts to show whether multiple profiles can be controlled by including a multiplier with the feature control frame.
In this question line video, we explain when to use the diameter symbol in a feature control frame. The examples below illustrate the unique tolerance zones shapes and sizes for position, perpendicularity, straightness, runout, and cylindricity controls.
Can you use the MMC modifier and still ensure a minimum wall thickness? To answer this question, we are going to look at a drawing of a flywheel and compare how using the MMC modifier or the LMC modifier affects the minimum wall thickness.
Why doesn't a feature of size that is indicated as a datum feature need to be located? In this article and corresponding question line video, we look at two drawing examples to illustrate why datum features are not located.
"Why doesn’t Rule #1 apply to the straightness of a Derived Median Line?" In this article, we look at both surface straightness and straightness of a feature of size to understand why Derived Median Line Straightness overrules Rule #1 of GD&T.
If I specify a hole in a practically thin feature, such as a piece of sheet metal, is this still considered a cylindrical datum? Is this a poor choice of datum? In this article, we look at an example to help us answer these questions.
Surface finish and flatness both limit the amount of variation in a surface – one at the micro level and one at the macro level. Is it permissible to call out both on the same surface?
In our video question line, our GD&T instructors answer questions submitted by our students. In this video, we answer the question, “Is the Virtual Condition the same as the Tolerance Zone?”
Preparing for the ASME GDTP exam? Our GD&T instructors share tips and experience for both Technologist and Senior-level certifications.
Molly Olson is one of our expert GD&T Instructors, with a wealth of valuable real-world experience in quality control and inspection. She has spent nearly 20 years as a Quality Inspector and CMM Programmer and Operator across several different industries, including aerospace, firearms, robotics, and prosthetics.
In this video, Jason explains how perpendicular datums can be derived from imperfect datum features.
We often see a pattern of holes indicated as a datum feature in a GD&T drawing. How do we simulate this to create our datum reference frame?
Is it allowable to have identical Virtual Conditions for mating boss and bore features? Watch this video to learn how to calculate and compare Virtual Conditions of mating features.
Can a single point (without clocking) be used as a secondary datum in a feature control frame? To answer this question, we first need to determine what datum feature is being represented by this single point. Read on to discover the answer to this commonly asked question from our GD&T students.
When applying position tolerances to countersunk fixed fastener assembly conditions, our design must not only ensure assembly, but also that the fastener head sits flush or below the surface of the part. We are able to determine the values required to achieve this by using the fixed fastener equation.
A chamfer is an edge feature commonly seen on part drawings, and consists of an angled cut on an internal or external edge of a part.
Fillets and rounds are both radial edge features, with fillets applied to internal edges and rounds applied to external edges.