circularity / diameter tolerance

[cervantes]

hello one more time,

well, haven't found exact answer anywhere yet so I am asking:

1) if there is a hole, with diameter let's say 50 and tolerance M6 and no form and position tolerance (circularity) is given on the drawing (and default workshop circularity is let's say 0.1mm) so then I can not exceed tolerance diameter range anyway, isn't true? otherwise it does not have sense in my opinion

in other words: DO I NEED to specify circularity for drawing with diameter 50M6?...

2) If statement above is true and circularity is specified, but with higer range, then M6 tolerance has priority anyway?

thanks in advance

 

[Occupant]

You are right, unless the required circularity is better than the restriction given by M6. Therefore, if circularity tolerance is given, it should always be less than the dimensional tolerance.

 

[dgallup]

For circularity to be a valid specification it needs to be a refinement of the size specification.

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The Help for this program was created in Windows Help format, which depends on a feature that isn't included in this version of Windows.

 

[Tmoose]

" DO I NEED to specify circularity for drawing with diameter 50M6 "

I'd say it could depend on the situation, notably the part function.

50 mm M6 = -4/-20 um.

If this is a high performance connecting rod journal (not the bore) the recommended roundness and taper should be 0.0002" or 0.0001" (5 um or 3 um) measured as a diameter.

http://www.cleviteonengine.com/publications/CEB-1-1208.pdf

 

[robyengIT]

If it can help