Engineers Edge

Circularity of hole Smile
Post Reply
 
Dimensioning & Tolerancing GD&T Forum
Posted by: ignatiuschew

10/01/2010, 21:50:38

Author Profile
eMail author
Edit

I have a hole diameter of 34.2 with tolerance of H8 (0/+0.039). Based on general tolerance standard ISO 2768m-H, what is the required circularity of this hole? Is it 0.02mm?
Please advice







Post Reply
Tell a Friend (must be logged in)
Alert Admin About Post
View All   Previous | Next |

 

Replies to this message

: Circularity of hole
: Circularity of hole -- ignatiuschew
Post Reply
Top of thread
Dimensioning & Tolerancing GD&T Forum
Posted by: Kelly Bramble

10/01/2010, 22:02:01

Author Profile
eMail author
Edit

Unless a Circularity tolerance is specified, there is none...

Though, technically for the ASME and ANSI standards, Circularity is included in the limnits of size specification. Which means, the hole is simply manufactured between the MMC and LMC size an all is accepted (Rule #1 should be considered).

If the engineering drawing standard is ISO 1101 - again the Circularity is included in the limits of size - but not Cylindricity.








Post Reply
Tell a Friend (must be logged in)
Alert Admin About Post
Where am I? Original Top of thread Previous | Next |
: : Circularity of hole
: : Circularity of hole -- Kelly Bramble
Post Reply
Top of thread
Dimensioning & Tolerancing GD&T Forum
Posted by: ignatiuschew

10/01/2010, 22:15:33

Author Profile
eMail author
Edit

Thanks Kelly,

But in the drawing, there is a callout for reference to ISO 2768m-H. Even though circularity was not call-out for that hole. Based on ISO 2768m-H we still need to follow the general tolerance. Am I right?

So based on the MMC and LMC size, is the tolerance supposed to be 0.02mm or 0.04mm (total tolerance range of the diamter)?








Post Reply
Tell a Friend (must be logged in)
Alert Admin About Post
Where am I? Original Top of thread Previous | Next |
: : : Circularity of hole
: : : Circularity of hole -- ignatiuschew
Post Reply
Top of thread
Dimensioning & Tolerancing GD&T Forum
Posted by: Kelly Bramble

10/01/2010, 22:41:50

Author Profile
eMail author
Edit

ISO 2768m-H is embraced in several GD&T standards, US and within the EU - such as EN 22768-2:1993

The specific notes on Circularity are:

"The general tolerance on circularity is equal to the numerical value of the diameter tolerance, but in no case shall it be greater than the respective tolerance value for circular radial run-out given."

So, MMC = (34.2 - 0) and LMC = (34.2 + 0.039)

The Circularity is built into the limits of size or is equal to 0,039 when some elements of the hole are manufactured at LMC and zero when all elements are manufactured at MMC.








Post Reply
Tell a Friend (must be logged in)
Alert Admin About Post
Where am I? Original Top of thread Previous |   |


© Copyright 2000 - 2022, by Engineers Edge, LLC All rights reserved.  Disclaimer