Do Brackets mean no tolerance 1

[peterjn]

Can someone point me to a reference for the following:
(.xxx) means no tolerance
This is on a drawing and I referred to the block for tolerances.
I believe I am correct referring to the block but I can't find a reference that by putting a dimension into brackets or () this means no tolerances.

Thanks for any help.

 

[ewh]

(XXX) is a reference dimension with no tolerance.

 

[fcsuper]

AMSE Y14.5M-1994 Paragraph 1.3.10 for definition and 1.7.6 for implementation. Basically, a dimension that is repeated, derived, or in some way auxillary is a reference dimension. Reference dimensions are identified by being placed within parentheses. ( ) They do not have a tolerence, nor do they govern production or inspection operations.

Matt Lorono
CAD Engineer/ECN Analyst
Silicon Valley, CA
Lorono's SolidWorks Resources
Co-moderator of Solidworks Yahoo! Group
and Mechnical.Engineering Yahoo! Group

 

[powerhound]

The parenthesis mean one of two things; either the same dimension is shown elsewhere on the print and is a hard dimension or it can be derived from other dimensions, inwhich case those dimensions are toleranced

Powerhound, GDTP T-0419
Production Supervisor
Inventor 2008
Mastercam X2
Smartcam 11.1
SSG, U.S. Army
Taji, Iraq OIF II

 

[ctopher]

This is sometimes confused with a secondary dim.
I have seen:
.123
(.2)
Thinking primary and secondary.
It should be:
.123
[.2]

(numbers are examples only)

The () is for reserved for reference dims.

Chris
SolidWorks 08 0.0/PDMWorks 08
AutoCAD 06
ctopher's home (updated 10-07-07)
ctopher's blog

 

[peterjn]

Thank you for the reference and answers, I have never seen this before (learned something today)

 

[fcsuper]

peterjn,

My I ask your background, careerwise?

Matt Lorono
CAD Engineer/ECN Analyst
Silicon Valley, CA
Lorono's SolidWorks Resources
Co-moderator of Solidworks Yahoo! Group
and Mechnical.Engineering Yahoo! Group

 

[peterjn]

Hi fcsuper,
My background is electrical & optical engineering.
I appreciate your help.
Thanks again,
Pete

 

[fcsuper]

Pete,

It's good to know the background. If you are going to be more involved with mechanical drafting, I recommend either a workshop or a JC class that covers ASME Y14.5M-1994. Best of luck!


Matt Lorono
CAD Engineer/ECN Analyst
Silicon Valley, CA
Lorono's SolidWorks Resources
Co-moderator of Solidworks Yahoo! Group
and Mechnical.Engineering Yahoo! Group