Alex Krulikowski

Here’s a question we received last week…

I have been talking with some drafters and engineers about the standard and have heard varying answers. I’m wondering about when you state the ASME Y14.5-2009 Standard on your drawing in a note or in a title block what it actually means.

Ex. “INTERPRET DIMENSIONING AND TOLERANCING PER STANDARD ASME Y14.5-2009″

Does it mean that the print will always be dimensioned using GD&T?

Does it force you to only dimension using GD&T, or can you use the basic limit dimensioning style?

Does the basic limit dimensioning style still fall under that standard?

Brian Mebruer
Cooper Industries

Great question! People often wonder if invoking the Y14.5 Standard means that they can no longer use limit dimensions (some call it coordinate tolerancing). The Y14.5 Standard does allow the use of limit dimensions. Also, when specifying the Y14.5 Standard, it invokes Rule #1, which helps to clarify where limit dimensions are used as size dimensions.

However, the Y14.5 Standard discourages the use of limit dimensions for locating features of size (i.e. holes, widths, tabs, etc.).

Using limit dimensions for locating features of size has three major shortcomings:

1. The square (or rectangular) tolerance zones are overly restrictive.
2. The tolerance zones are always a fixed size.
3. There are no specifications for how to hold the part for measurement.

The first two shortcomings result in less tolerance for manufacturing. The third shortcoming of limit dimensioning is that it results in confusion or disputes over inspection results. The lack of datum specifications leaves the drawing with at least several interpretations.

I hope this helps.

Alex

Earlier this month, I blogged about my new geometric tolerancing book that explains the use of ISO standards on technical drawings:

Alex Krulikowski’s ISO Geometrical Tolerancing Reference Guide

It’s a comprehensive book that can be used to learn the topic, and it’s also a great reference guide. The book is based on ISO 1101-2004 and companion standards.

ETI is offering a course this fall that utilizes the new book. The ISO Geometrical Tolerancing 3-day workshop will be held September 29th – October 1st, here in the Detroit area. The three-day ISO workshop will help you to understand engineering drawings that use the International Standards Organization (ISO) standards.

The course was written with three goals in mind:
1. To help you recognize what is required on a good (standard-compliant) drawing
2. To help you understand geometrical tolerances based on the ISO standards
3. To combine and explain information from dozens of ISO standards into a logical understandable topic

You’ll learn about …

• ISO drawing conventions
• GPS basics
• Limits and fits
• The datum system
• Form controls
• Orientation controls
• Location controls
• Run-out and profile controls
• General tolerances
• Workpiece edges
• Surface texture
• How ISO compares to ASME

If your company is interested in global sourcing and learning how to read drawings created in other countries, this workshop is vital to your success. It will teach you the ins and outs of utilizing the ISO standards and will give you a fundamental knowledge of ISO 1101:2004, related standards, and their application on drawings.

Those who attend the workshop will receive:

• Alex Krulikowski’s ISO Geometrical Tolerancing Reference Guide
• An ISO Geometrical Tolerancing Workbook
• Class handouts
• An official certificate of completion

Read more about the course and specific topics here. I hope to see you in the Detroit area for this exciting new workshop.