Hole Tolerance Question
Hole Tolerance Question
(OP)
Hello,
I am trying to perform a tolerance stack up on a small assy. I have:
Block w/ Hole ID - 0.309 +/- 0.002
Bushing OD - 0.307 +/- 0.005
Bushing ID - 0.250 +/- 0.005
Pin OD - 0.244 +/- 0.002
I want to put the bushing into the hole and put the pin into that. I have never done a tolerance stack up on anything except examples (none of which I had anything like this).
Right now, my idea is to cut it in half and just do half of the stack up so it represents a more simple stack up.
Could someone give me direction on how to do this?
Thanks,
J
I am trying to perform a tolerance stack up on a small assy. I have:
Block w/ Hole ID - 0.309 +/- 0.002
Bushing OD - 0.307 +/- 0.005
Bushing ID - 0.250 +/- 0.005
Pin OD - 0.244 +/- 0.002
I want to put the bushing into the hole and put the pin into that. I have never done a tolerance stack up on anything except examples (none of which I had anything like this).
Right now, my idea is to cut it in half and just do half of the stack up so it represents a more simple stack up.
Could someone give me direction on how to do this?
Thanks,
J





RE: Hole Tolerance Question
Worst case fit of the bushing into the block is minimum block hole dia - maximum bushing OD. So .307-.312 so .005 interference - which may be a bit aggressive depending on factors you don't list.
Likewise Min bushing ID -max pin OD. So .245-.246 = .001 interference which again I don't know if that's appropriate for your application or not.
If you want to find max slop then do the opposite calculation.
What is Engineering anyway: FAQ1088-1484: In layman terms, what is "engineering"?
RE: Hole Tolerance Question
Right now it seems that all fits are transition. You just need to compare:
#1:
a) min. ID of hole with max. OD of bushing;
b) max. ID of hole with min. OD of bushing;
#2:
a) min. ID of bushung with max. OD of pin;
b) max. ID of bushing with min. OD of pin;
In both cases there will be an interference in a)'s and a loose in b)'s, so this is typical transition fit.
RE: Hole Tolerance Question
My question was not using worst case, I figured that out. I was wondering if I was using the RSS, more specifically if it was okay to take off from the outside to the center and then just double everything to get the entire hole tol.
Thanks,
J
RE: Hole Tolerance Question
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RE: Hole Tolerance Question
RE: Hole Tolerance Question
With that said, it will fit down to a .305 hole if my math is correct, before that gap closes. Thus making it a slip fit all the time.
My asking for the RSS tolerance stack up is mearly because I am not sure if my method of doing this (in this scenario) is correct and I wanted to see if someone could tell me if my method works.
WC right now, I believe will have a .006" press fit. I would rather it be slip fit because we are putting a rivet (the pin) through the center and right now I am not sure how much that will expand.