×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Check Dimension

Check Dimension

Check Dimension

(OP)
Hello,
it seems a simple question but I fail to find any concrete answers on this online.
If a drawing show a dimension with rounded brackets it is referred to to be a "checking dimension".
When "100%" is added then this would mean that all parts are checked, so 100%, correct?
When "SPC" is added then this would mean that a large number of parts are manufactured, then measured and then the capability cpk derived from it to understand the process capability thus getting a confidence that the process is stable and not all parts need to be measured but only a few, say for each batch or at the beginning of each shift etc, correct?
So now, if there is only the rounded brackets but no SPC or no 100% the official information I find state that this means "needs to be measured". My question is, how often? Is there a standard / ISO that defines this or do we have to specifically clarify this with the supplier?

Thanks!

RE: Check Dimension

A "check dimension" such as you describe is usually for a surface or distance that is readily measured - but is buried somewhere in among a bunch of other dimensions that are not so readily verified after manufacture / assembly. It is called a "check" because the exact measurement isn't important as long as the remainder of the surfaces / distances that define it ARE within correct tolerance.

As an example: If I handed you a stick that was exactly 1 meter long, with two marks on it (one at the 15 cm position and one at the 65 cm position), the resulting "check" dimension would be the distance you could measure between the two marks: 65-15 = 50 cm.

As a further example: If I handed you the same stick without telling you it was exactly a meter long, but gave the distance from mark to end AND the distance from mark to mark, then the overall length (1 m) would become the check dimension.

Converting energy to motion for more than half a century

RE: Check Dimension

If by rounded brackets you mean parentheses, then it's a reference dimension and it should not be measured.

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members! Already a Member? Login



News


Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close