Quick parallelism question
Quick parallelism question
(OP)
Datum A has 2 surfaces parrallel to it. One surface to the right of Datum A, and 1 to the left of Datum A. Should there be 2 seperate dimensions originating from Datum A with 2 seperate parralelism callouts, or can you dimension from Datum A to one surface, and then a second dimension from the first surface to the second surface with 1 feature control frame? I'm looking at a drawing dimensioned the second way. The first dimension does not have feature control frame, but the second dimension does. The intent of the designer is to have each surface parralel to Datum A within the same tolerance.





RE: Quick parallelism question
What is Engineering anyway: FAQ1088-1484: In layman terms, what is "engineering"?
RE: Quick parallelism question
If you are able to post a sketch, that always helps.
John-Paul Belanger
Certified Sr. GD&T Professional
Geometric Learning Systems
http://www.gdtseminars.com
RE: Quick parallelism question
RE: Quick parallelism question
The way you specify the parallelism to datum A is in the FCF(s) not the dimension scheme.
What is Engineering anyway: FAQ1088-1484: In layman terms, what is "engineering"?
RE: Quick parallelism question
IMO either method described is valid.
If you have a dimension from Dat A to one side and an overall dimension;
or two dimensions from Dat A to each surface (more tolerance stack); or basic
dimensions with a profile control; all dimensional schemes are locating those surfaces.
The parallelism (orientation) back to Dat A would prescribe a boundary of 2
parallel planes (for each parallel control) which are aligned / oriented
in relationship to Datum A as a refinement
of orientation to those surface within the size limits.
RE: Quick parallelism question
RE: Quick parallelism question
Thanks again!