Need advice on giving tolerances on drawings for parts
Need advice on giving tolerances on drawings for parts
(OP)
I am a design process engineer. i used to work for Tool and die company. I was told to do the design and general dimensions, and the boys on the floor making the stuff would do the tolerance of fitting the things. I need some advice on specifying tolerances over distances and as in cut and protrusions. anything that could help please as its holding me back.....
I know that any tolerance on a protusion on a component say must be taken in to account over the over all dimesnion as in they small dimensions with tolerance must not exceed the overall diension and its tolerances. I need help anything to make me better at it.
I know that any tolerance on a protusion on a component say must be taken in to account over the over all dimesnion as in they small dimensions with tolerance must not exceed the overall diension and its tolerances. I need help anything to make me better at it.





RE: Need advice on giving tolerances on drawings for parts
Chris
Systems Analyst, I.S.
SolidWorks 06 4.1/PDMWorks 06
AutoCAD 06
ctopher's home (updated 06-21-06)
RE: Need advice on giving tolerances on drawings for parts
This question might be better placed in forum1103
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RE: Need advice on giving tolerances on drawings for parts
RE: Need advice on giving tolerances on drawings for parts
The first and best reference I ever had was BS 308 - I think it's now part 2 of the Standard that covers dimensioning and the effects of cumulative tolerances. As you say in your example, you can't have the cumulative sum of tolerances within a feature exceeding the overall tolerance of that same feature. You have to make the judgment (based on priority of function) which is the most important - the individual elements or the overall. There are so many different ways of detailing the dimensions and their tolerances, the final decision has to be yours. You could try looking at similar drawings already created within your Company to see how others have resolved the question. There might be a Company “customs and practice” in place that says “this is how we want it done” but more likely the answer will be evident when you look at the essential function of the component and how it interacts with other mating components. Sorry - no easy answer !
RE: Need advice on giving tolerances on drawings for parts
Depending on what country you're in will depend which spec you probably want to refer to. If US then Y14.5, in the UK the BS.