Sphere form tolerance Question
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Posted by: Hup23Hup ®

04/16/2007, 04:55:13
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I am measuring a sphere on a CMM and the sphere is measuring too big. However, take more points and it averages out O.K.
When I measured the form of the sphere in is .060 of a mm. This I believe is way too big. The drawing does not state a sphere form tolerance. What is a recommended sphere form when the drawing does not specify one?

Thanks,
M








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Re: Sphere form tolerance
Re: Sphere form tolerance -- Hup23Hup Post Reply Top of thread Forum
Posted by: Kelly Bramble ®

04/16/2007, 07:52:16
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Regardless of which three points your measure from, if you measure larger than the maximum material condition given by the limits of size, then it is too large. If there is not a form tolerance specified, then one is not measured. If the drawing is interpreted per ASME Y14.5M-1994, then MMC is a boundary that may not be encroached or violated (part measures larger than) by the combined effects of form and size. So, if the part is manufactured at MMC it has to be a perfect sphere. Technically, the sphere is form controlled by default from the limit tolerances. The part can vary between MMC and LMC and this is the form limits as well.







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Re: Re: Sphere form tolerance Agree
Re: Re: Sphere form tolerance -- Kelly Bramble Post Reply Top of thread Forum
Posted by: Hup23Hup ®

04/17/2007, 07:54:42
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Thanks Kelly.
V. Informative and clear.

Hope I can help you out sometime.








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