What you speak of isn't uncommon. I have seen drawings with dimensions on one side and a note stating "SYMMETRICAL ABOUT CL". However, I believe it is still ambiguous. For example, the features on the right hand side are inspected from the right hand edge, are the features on the left hand side...
Nereth1,
If you dimension and tolerance from an edge to a center line, then dimension and tolerance other features off that center line, wouldn't you just be introducing additional tolerance accumulation vs. just dimensioning all features from that edge? I don't see any added benefit to such a...
ASME Y14.5-2009 section 1.7.6
"The method for identifying a reference dimension (or reference data) on drawings is to enclose the dimension (or data) within parentheses. See Figs. 1-19 and 1-20."
If the two keyseats are in the bore, I would recommend making the bore the primary datum feature.
I don't think it is necessary to make one of the keyseats a secondary or tertiary datum feature to control their relationship to eachother. Since the keyseats are a pattern of features, you can use...
dtmbiz,
You requested that I share the definition of assembly from ASME Y14.24. Here is the definition from Mandatory Appendix I - Definition of Terms:
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assembly: a number of parts or subassemblies or any combination thereof joined together to perform a specific function, and...
ASME Y14.24-1999, 1.9:
"The characteristics of more than one drawing type may be combined into a single drawing provided the resulting combination includes the data required by the individual types. Fore example: a modification kit drawing combines a description of the modification and the kit...
I agree. I think any company implementing a new dim and tol standard should take great care in making sure they are selecting the proper controls to assure they are defining the required relational and functional geometry of their parts. It is easy for us (engineers) to make manufacturing and...
You may add cost in the form of upfront drafting time and training. However, if you are currently controlling geometric relationships with lengthy notes, your drafting time may stay the same or even decrease.
We once outsourced the machining for a set of LARGE wheel hubs. The tolerances were...
I did not communicate that linear or angular tolerances have no place (nor did Tech-Ease).
We make drawings using line conventions, orthographic projections, title block information, bills of material/raw material specs, surface texture requirements, weld symbols, local and general notes...
Dave, I think GDT trainers, such as yourself, are indispensable since many colleges do a poor job training engineers in technical drawing. They must think we still get our own draftsman to make the drawings for us. :)
I guess the point I'm trying to make is that at some point it becomes beyond...
Applying no requirement at all and assuming the part will function properly obviously did not help either...
How do you know the note is applying the correct requirement? What's the difference between applying the wrong requirement in note form or symbol form?
"The primary problem I find with GD&T is it requires a Designer/Drafter who can write/read it, a fabricator who can read it and an inspector/quality engineer who can read it."
That's the primary problem with English, algebraic expressions, surface roughness requirements, heat treat...
"GD&T seems to work best if you keep it simple; some of the extreme GD&T examples in the book are difficult for everyone in the process to comprehend, so the meaning tends to get lost (there are exceptions)."
I would say having one datum feature symbol and a runout or position tolerance is as...