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【转帖】hread depth in a pocket slot gdt callou

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发表于 2009-5-4 10:42:07 | 显示全部楼层 |阅读模式
thread depth in a pocket & slot gd&t callout
are thread depths the same as counter bores in there interpretation?
is either slot callout correct?
please view the attached pdf and let me know which are the correct callouts.

in the positional tolerance of the slot, b, is correct. a references the slot with a diametrical tolerance zone but the feature of size is not round. b is absolutely correct.
i also like b in the dimensioning the depth of the thread since it came from a base line rather than chain dimensioning.   
dave d.
asme y14.5m-1994 1.8.11 (fig. 1-37) should answer the first portion.
5.10.1 (fig. 5-47) illustrates an example of a slot.
re: fig. 1-37
i never realized that a depth callout of "3" is to be interpreted as "13".   
the edge... there is no honest way to explain it because the only people who really know where it is are the ones who have gone over.fff"> - hunter s. thompson

ewh:
you misinterpreted 1-37. it means that the largest counterbore of 10 mm has a depth of 3 mm.
dave d.
oh!! (as the light hits my eyes)
now i understand.  thanks!
the edge... there is no honest way to explain it because the only people who really know where it is are the ones who have gone over.fff"> - hunter s. thompson

threads are the same as counterbores for interpretation.  b is correct for the threads - as dingy2 said, it avoids chain dimensioning and it simplifies inspection because you measure from an easily accessible feature (the large outer surface).
having said that, the actual numbers on your example make no sense.  the two counterbore depths equal the thread depth, so there is no available material to make the threads.
regards,
cory
cory is correct on the dimensioning conflict.   
dave d.
what dingy & cory?  
b is most correct interpretation on the thread callout given top left however, counterbore symbols would probably be needed to clarify the callout, there is no dimensioning conflict.  the depths for round holes are measured from the surface uos.
quote (asme y14.5m-1994  1.8.9 of ):
the depth dimension of a blind hole is the depth of the full diameter from the outer surface of the part.
this is illustrated for c'bores in figure 1-37 mentioned above.  
the first c'bore has a depth of .125 from surface, second is .250 from surface, thread is .375 from surface so you end up with .125 of thread (.375-.250).
for the slot b is more correct though you may want to consider adding 'boundary' - see the reference weavedreamer gave.
kenat,
i retract my previous statement regarding no material available for the threads.  i was thinking about chain dimensioning, not paying attention, so thanks kenat for correcting me.
after closer scrutiny, the axial thread engagement is approximately equal to the thread diameter, which is a common ratio used for joints that have similar materials for the internal and external threads.
regards,
cory
kenat:
yes, i agree with you on the dimensioning. looks like cory and i must have had the same breakfast.
dave d.
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