Looking for clarification on Y14.5-2018 Paragraph 3.35.1

[Alexander Mc]

Hi, I'm new to this forum. I apologize in advance if this seems like a silly question or has already been asked.

I'm looking for some clarification in Y14.5-2018 paragraph 3.35.1 for type A and type B.

I somewhat understand the concept. However, Figures 7-40 and 7-41 don't make any sense to me.

Figure 11-29 on the other hand is better. This may be a dumb question, but would the cut out in this figure be considered type A or B? And why?

Thanks for your help.

 

[jassco]

Hi, Alexander:

What does not make senses to you regarding Figures 7-40 and 7-41? They make a lot of senses to me.

Best regards,

Alex

 

[axym]

Alexander,

Believe me, many of us have looked for clarification on irregular features of size Type A and Type B. To me, the irregular features of size section is not one of Y14.5's finest moments. It relies on definition by example, and the definitions do not make it easy to generalize outside of the examples that are shown. There are Here is my best understanding of it:

The feature in Figures 7-40 and 7-41 is an example of Type A. It is a collection of features that can contain or be contained by an unrelated AME that is a sphere, cylinder, or pair of parallel planes. The feature is comprised of three cylindrical segments whose surfaces are not directly opposed, and thus do not qualify as a regular cylindrical feature of size. But together they form enough of a cylinder that they that can hold a cylindrical counterpart (pin) that can be used to establish a datum axis. The "means this" figure shows the irregular FOS "containing" the solid cylinder.

The asymmetric cutout feature in Fig. 11-29 is an example of Type B. It would not contain an unrelated AME that is a sphere, cylinder, or pair of parallel planes (at least not with proper contact).

Evan Janeshewski

Axymetrix Quality Engineering Inc.

http://www.axymetrix.ca