Feature control frame with basic dimension for coplanar surfaces?
Feature control frame with basic dimension for coplanar surfaces?
(OP)
Dimensions are in mm. What would the tolerance be for the feature control frame "3.730 8x" dimension? The block tolerance on the print is +/- 0.125mm. I am told that the print block tolerance does not apply. I have never seen T.I.R in a feature control frame for flatness or parallelism with a basic dimension framed for the distance. What is the tolerance of the 3.730 8x dimension?





RE: Feature control frame with basic dimension for coplanar surfaces?
It's very hard for us to image what it looks like for a section view only, would you mind to post a whole picture.
I have never seen not only TIR in a FCF but also the datum (-A-) and quantity (8X) callout, what standard apply for the print ? Y14.5 or ISO ?
SeasonLee
RE: Feature control frame with basic dimension for coplanar surfaces?
If coplanarity it desired, then profile of a surface would have to be used.
John-Paul Belanger
Certified Sr. GD&T Professional
Geometric Learning Systems
RE: Feature control frame with basic dimension for coplanar surfaces?
I won't comment on Y14.5 as I am not familiar with it but here is my interpretation of the section drawing you have posted:-
TIR = Total Indicator Reading
8x = feature is in 8 different positions
So the parallel tol 0.1 for the 3.730 basic dimension means that the dimension can be 3.68 or 3.78 and that is repeated 8 times over the component.
desertfox
RE: Feature control frame with basic dimension for coplanar surfaces?
Powerhound, GDTP T-0419
Engineering Technician
Inventor 2010
Mastercam X4
Smartcam 11.1
SSG, U.S. Army
Taji, Iraq OIF II
RE: Feature control frame with basic dimension for coplanar surfaces?
TIR is total indicator reading, but I think it's extraneous and doesn't add anything to the print.