×
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!
  • Students Click Here

*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

Jobs

Meaning of T on Concentricity
2

Meaning of T on Concentricity

Meaning of T on Concentricity

(OP)
Please ref to the attached figure, what is the meaning of T on Concentricity callout?

Thanks for your assists

SeasonLee

RE: Meaning of T on Concentricity

What drafting standard is it meant to be to, ASME Y14.5M-1982?

(I love the coffee stain by the way, and I'm guessing this isn't your drawing etc. but before someone else says it, it shouldn't say reamed on the .188 dia call out.)

Posting guidelines FAQ731-376: Eng-Tips.com Forum Policies http://eng-tips.com/market.cfm? (probably not aimed specifically at you)
What is Engineering anyway: FAQ1088-1484: In layman terms, what is "engineering"?

RE: Meaning of T on Concentricity

The only T modifier I know is tangent plane and it is a "circle T". If the intent was to somehow invoke "tangent plane" then this is incorrect and cannot be checked. There should be a diameter symbol before the tolerance value so that much is wrong with this specification as well.

Powerhound, GDTP T-0419
Engineering Technician
Inventor 2010
Mastercam X5
Smartcam 11.1
SSG, U.S. Army
Taji, Iraq OIF II

RE: Meaning of T on Concentricity

Total indicator reading / movement?

RE: Meaning of T on Concentricity

Good point CH. Tec-ease has a tip this month about what was allowed on older standards and the word TOTAL used to be allowed in the FCF. Maybe it's a pre-1973 standard print and the T is supposed to mean "TOTAL".

Powerhound, GDTP T-0419
Engineering Technician
Inventor 2010
Mastercam X5
Smartcam 11.1
SSG, U.S. Army
Taji, Iraq OIF II

RE: Meaning of T on Concentricity

T is tangent plane and is inappropriately used on concentricity.

Dave D.
www.qmsi.ca

RE: Meaning of T on Concentricity

I agree it is most likely a left over from TIR.
Frank
 

RE: Meaning of T on Concentricity

(OP)
The only one T symbol example on the 2009 STD is FIG 6-18, which is applied on parallelism callout; can we use it on the other callout? Say flatness, straightness, or .....

SeasonLee

RE: Meaning of T on Concentricity

What is the advantage of applying Tangent Plane to Internal Diameter?

RE: Meaning of T on Concentricity

Season ... Tangent plance can't be used on flatness or straightness because the definition of tangent means that it ignores flatness/straightness.  It only checks the highest points (tangent plane).   The circled T can be used on parallelism, perpendicularity, angularity, and even profile of a line/surface (although the standard doesn't explicitly say profile, it's implied by the note in the text).  Maybe even runout could use the T.

John-Paul Belanger
Certified Sr. GD&T Professional
Geometric Learning Systems
http://www.gdtseminars.com

RE: Meaning of T on Concentricity

(OP)
But, circle T can not applied on Concentricity callout for sure, right?

Season
 

RE: Meaning of T on Concentricity

Right, because of the definition of concentricity, which specifies the "median points" of diametrically opposed elements, blah, blah...

John-Paul Belanger
Certified Sr. GD&T Professional
Geometric Learning Systems
http://www.gdtseminars.com

RE: Meaning of T on Concentricity

(OP)
One more question : When should we need the tangent plane symbol in FCF after stated tolerance.

Thanks

SeasonLee

RE: Meaning of T on Concentricity

2
If you want to allow the form error to be greater than the given tolerance (such as for parallelism).  An example would be a simple mating surface, where we don't really care about pits/valleys, but we do care about peaks since they will make the part sit at a different angle.  Don't use T if the mating surface is a sealing surface where you are are worried about leakage.

John-Paul Belanger
Certified Sr. GD&T Professional
Geometric Learning Systems
http://www.gdtseminars.com

RE: Meaning of T on Concentricity

(OP)
Thank you all, it makes me clear in a short time.

SeasonLee

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!


Resources