×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Are you an
Engineering professional?
Join Eng-Tips Forums!
• Talk With Other Members
• Be Notified Of Responses
• Keyword Search
Favorite Forums
• Automated Signatures
• 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.

# Conversion of orthogonal tolerances to round tolerance zones

## Conversion of orthogonal tolerances to round tolerance zones

(OP)
Hello,

TLDR: How should I use G,D T to show a square/rectangular tolerance zone around the FOS regardless of the shape of the feature?

Simple scenario: a hole is dimensioned using a +- tolerance scheme and say the X, Y locations are (10+/-0.25, 12+/-0.25). Now, if we apply G,D and T to this, we can convert this to a circular tolerance zone with a radius of 0.25*sqrt(2)=0.35, or dia 0.7 thereby gaining more tolerence. My question is - have we made the implicit assumption here that the designer made an oversight here i.e. he could've gotten away with more tolerance (0.7) than he toleranced the position of the hole at.

What if he really wanted the orthogonal position tolerances? i.e. he chose the tolerances after considering tolerance stack-ups along the two axes. Moreover, what if the tolerances were more in one axis than the other? I've seen some G,D,T reference books which have a chart for converting the coordinate measurements to round tolerance zones even if the tolerances in both axes are not the same. I found this confusing and I feel like I'm missing something here.

Thanks!
Sid

### RE: Conversion of orthogonal tolerances to round tolerance zones

If you have access to Y14.5-2009, you may want to take a look at fig. 7-28 (in Y14.5M-1994 it is fig. 5-41).

### RE: Conversion of orthogonal tolerances to round tolerance zones

(OP)
Perfect! Much Thanks!

#### 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.

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:

• Talk To Other Members
• Notification Of Responses To Questions
• Favorite Forums One Click Access
• Keyword Search Of All Posts, And More...

Register now while it's still free!