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Worst Case Tolerancing

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FM44

Mechanical
Jun 28, 2007
5
Hi,
Can any one, please, answer the following question in laymen terms:
- if I am doing a simple "worst case" tolerance analysis, how many pairs of the extreme dimensions do I consider?
example:
I have a pair of bayonet hooks (plastic part), which are 2.00 inches apart.(with +/-.01 tolerance.
The mating hooks are 2.01 inches apart (with +.02/-0 in.)
Which worst cases and how many pairs am I supposed to consider.
should they be as follows:
Max Bayonet-Min hook= x1
Min Bayonet-Max hook=x2
Min Bayone-Min hook=x3
Max Bayonet-Max hook=x4

Are these enough combination?
Please help!
thank you.

FM
 
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Max Hook (2.00 + .01)- Min match (2.01-.00)
Min Hook (2.00 - .01) - Max match (2.01 + .02)

Not accounting for location of the hooks, as you described, this is only the dimensional between the hooks.
 

monkeydog,
I appreciate your help.
From this point onward, I am assuming, I should pick such a range of tolerance that there will always be some clearance between the mating features.
Right?
Thank you.

FM44
 
Yes, if clearance is what you want.
ANSI Y14.5M is the governing document on tolerancing, but there are other books on the subject.
 

monkeydog/vims,
Thank you for your help. Even though the assembly is more complicated and I just presented it in simplest terms, just to understand the basics. I should be able to take it from here.
I appreciate your time and help.


Farid
 
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