ASME promotional material on GD&T - does this look professional?

[Burunduk]

Does this look professional to you?
I'd say that some of the things the interviewed person says make it sound like he is not well-versed on the subject.
The examples he shows from the drawings he works by have some alarming things in them too.

What is your opinion?

"How do you make parts for the Mars Rover? With GD&T"

 

[3DDave]

Let me find the standard titled "Geometric Dimensioning and Tolerancing" and we can find out.

Alarming? Alarmingly common, no doubt.

The countersink example - unless the position tolerance is less than the screw clearance then a group of flat-head screws going into countersinks will only line up by deforming the part in some way.

It reinforces my assertion that largely the CNC equipment exceeds the precision demanded by an order of magnitude so few are exposed to the effects of the applied tolerances. As a result, since even bad work on the drawing sees working parts from the factory there's no benefit for them to investigate further.

From the 301-20-23 is this oddity. Why would allowing the part to tilt even slightly with the (M) applied to the primary datum callout be a thought? Why would the secondary datum callout be one that had no influence? Answer - because it very likely doesn't matter. It's all in one setup and the machine precision exceeds the allowable variation.

 

[Belanger]

I didn't watch the entire vid yet, but I notice a total runout tolerance with the MMC modifier. Ouch -- good luck with that.



John-Paul Belanger
Certified Sr. GD&T Professional
Geometric Learning Systems

 

[Burunduk]

Good catch John-Paul, I now noticed that too.
I wonder how come ASME pubishes such amateurism.
Couldn't they involve a professional consultant?

 

[3DDave]

The person is a professional, just not an expert. The same is true of those who made the drawings.

I wonder if they will take this video down. They took down their GDTP quiz after I noted that the correct answer to a particular question was not in the selection of the multiple choices.