ISO 2768

[Madhu454]

Hi All,
Please help me to understand the confusion with using general tolerances as per ISO.
Question: If the drawings is made as per ISO standards, and no tolerances specified. Which grade of ISO 2768 is applicable? The drawing does not say anything about the grade to be followed (Like H, K or L).
Please help me to find answer for this.

 

[CheckerHater]

If no grade is specified, no grade is applicable

"For every expert there is an equal and opposite expert"
Arthur C. Clarke Profiles of the future

 

[CheckerHater]

Sorry for "dry" answer. Here is your reference.

"For every expert there is an equal and opposite expert"
Arthur C. Clarke Profiles of the future

 

[juergenwt]

Look for a note on the print like: Tol. as per ISO 2768 -f, -m, -c, or -v. These are for lenght, broken corners or angles.
-H, -K, -L are for for gen. tol. of straightness, right angle, roundness etc. in other words they are for Form and Position.
You could have an entry like: Print as per ISO 2768-m or an entry like: as per ISO -K or an entry like: as per ISO -mK.
If there is no entry after ISO 2768 than the designer forgot or did not know.

 

[Madhu454]

Hi All, Thanks for your reply.
In the example you shared "ISO 2768-m" , there is no grade specified for the geometrical requirements. Is this complete/correct? Since ISO drawings are based on Independency rule (unless we use E modifier) how the geometrical requirements are controlled?

Question; Is it allowed to skip geometrical grade and mention only dimensional grade like "ISO 2768-m"

Thanks for your time in advance.

 

[KENAT]

Question; Is it allowed to skip geometrical grade and mention only dimensional grade like "ISO 2768-m"

I believe so, but it's been a while since I looked at the spec.

Posting guidelines faq731-376

http://eng-tips.com/market.cfm?

(probably not aimed specifically at you)
What is Engineering anyway: faq1088-1484​

 

[juergenwt]

ISO 2768 applies only when no NO other tolerances - whether length, angles or form and positioning tolerances are listed on the print. So "yes" you could have ISO 2768 -m
without a grade for geometrical requirements if those requirements are listed separately in other forms on your print. Same-you could have ISO 2768 -K listed and NO -m or any other grade if tolerances for length and angles are listed on the print in any other form or way like for instance a "common shop tolerance".