ASME Drawing Standards - Metric 1

[Gary L]

Quick question from the UK . . .

I don't have access to the ASME Drawing standards - I can't justify the cost and Google hasn't been able to help me.


When a mechanical drawing is created to the ASME Standards should it be in English/Imperial units, or can it be created in Metric?

In this article on Lnkedin ...
What are the benefits and challenges of using ASME or ISO drawing standards in a global market?

... it states that "For example, ASME uses inch-based units, fractional dimensions, and bilateral tolerances, while ISO uses metric units, decimal dimensions, and unilateral tolerances."

Is that statement completely accurate ?

 

[Belanger]

Hello from this side of the pond!
This quote is from ASME Y14.5-2018, paragraph 4.2:
"For uniformity, all dimensions illustrated in this Standard are given in SI units UOS (unless otherwise specified). However, the unit of measure selected should be in accordance with the policy of the user."

Subsequent subparagraphs state:
"4.2.1 SI (Metric) Linear Units
The SI linear unit commonly used on engineering drawings is the millimeter.
4.2.2 U.S. Customary Linear Units
The U.S. Customary linear unit commonly used on engineering drawings is the decimal inch."

So it's essentially up to you (or the boss, the customer, etc.).



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

 

[Gary L]

Hey John-Paul

Thank you. That is really helpful.
There is a team in my organisation that 'needs' to follow ASME for a specific project.
One of the team has a vague understanding of the standard, but didn't know about the units.

It would have been a nightmare for us to swap to Inches for just one product line. Fortunately, it looks like we can get the models completed in Metric, and get hold of the standards to make sure that everything else is up to what is required.

Cheers
Gary

 

[ctopher]

You can also use duel dimensions.
in/[mm] or mm/[in]

Chris, CSWP
SolidWorks
ctophers home

 

[3DDave]

dual

 

[ctopher]

Thanks, missed that.

Chris, CSWP
SolidWorks
ctophers home

 

[dgallup]

I despise using dual dimensions. I've been designing metric products in the US for over 40 years and only use dual dimensioning when somebody holds a gun to my head. Suppliers will try to use the secondary dimensions for layouts, inspection reports, etc. You will fight round off errors, tolerances, gauge accuracy issues, etc. You also open a can of worms for default tolerances as most people using ASME Customary (inch) units are used to using the number of decimal places to denote tolerances. If it's a metric produce keep everything metric.

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The Help for this program was created in Windows Help format, which depends on a feature that isn't included in this version of Windows.

 

[Gary L]

We definitely won't go down the dual dimension route - And if anyone else suggested it, we will probably end up in a duel.

The team actually want to move towards MBD (Model Based Definition) and so are keeping the number of drawings to a minimum. I'm glad that ASME allows a choice between Inches and mm though, because the 3D models have already been created in metric and if someone interpreted the models wrongly we could end up with a product that was 25.4 times too big.

MBD standards are a whole new topic for us to learn . . . but that is something for later in the year !

 

[ctopher]

We are also moving to the MBD world.
A PITA to do it in SolidWorks.

Chris, CSWP
SolidWorks
ctophers home

 

[Gary L]

We are using a combination of Solidworks and Onshape. Existing products are in Solidworks, but most new projects are being kicked off in Onshape

I expect all MBD projects will be in Onshape.

 

[looslib]

Where I used to work, we did all metric designs but the drawing formats were in traditional A, B, C, D and E drawing sizes to fit US plotters and paper.
We did not do dual dimensioning. We did do an English-Metric table on Unigraphics drawings as it was easy to automate with GRIP. When we switched to Pro/Engineer, we had to drop the table as we did not have the tools to extract and convert the dimensions for the conversion table.

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