Positional confusion
Positional confusion
(OP)
you guys really help me out here, and am always performing searches to find answers
this time i have looked and cannot seam to find a thread with what im looking for.
i have the attached part come into quality assurance today & the inspector is asking me if he can hold it between centers & use a dial indicator on exterior Ø to measure the true position of the .569 hole.
weather he holds the exterior Ø in a v-block and runs indicator down the hole, or uses centers and runs the indicator over the exterior Ø does it matter?
this time i have looked and cannot seam to find a thread with what im looking for.
i have the attached part come into quality assurance today & the inspector is asking me if he can hold it between centers & use a dial indicator on exterior Ø to measure the true position of the .569 hole.
weather he holds the exterior Ø in a v-block and runs indicator down the hole, or uses centers and runs the indicator over the exterior Ø does it matter?





RE: Positional confusion
RE: Positional confusion
Frank
RE: Positional confusion
Frank
RE: Positional confusion
Also, FYI, datum B adds no value at all to this tolerance, although it's not wrong to have it there.
John-Paul Belanger
Certified Sr. GD&T Professional
Geometric Learning Systems
http://www.gdtseminars.com
RE: Positional confusion
It seems like the only was to mount this without potentially skewing the results is to mount on the OD.
Han primo incensus
RE: Positional confusion
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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.
RE: Positional confusion
Jim Sykes, P.Eng, GDTP-S
Profile Services www.profileservices.ca
TecEase, Inc. www.tec-ease.com
RE: Positional confusion
My guess is, yes
Frank
RE: Positional confusion
Possibly at some point it was automatic, but today note like "PERFECT COAXIALITY AT MMC REQUIRED" is recommended.
RE: Positional confusion
What has coaxiality to do with envelope principle? Am I missing something?
RE: Positional confusion
I couldn't find it in any modern standard, but some book suggested to use the note if you want to imply relationship between OD and ID without using GD&T symbology.
Not like I cared much about using such note, but Franc asked about OD and ID being affected by envelope requirement, so here you go.
RE: Positional confusion
Sorry for the confusion, I mean each of those features separately.
Frank
RE: Positional confusion
Just brought up another interesting topic.
RE: Positional confusion
RE: Positional confusion
Thanks!
RE: Positional confusion
Frank
RE: Positional confusion
First to the OP, I am not an inspector only a theorist, but my answer would, naturally, be the opposite of the others. I have been waiting for them to fill you in with the good relevant data before I took off. There doesn't appear to be much they can offer, but, make a gage or in essence the same response. How do they think we all get our work done without gages anyway and it goes to my issue with the standard and gages that I have started elsewhere?
Naturally, it is always best to check as directed but if you can't you're going to do the best you can with what you have. To me the answer is you need to check many other things if you are not going to check what is actually asked directly to make certain to the best of your ability you have achieved the requirement stated on the drawing. Your proposed method could then be part of a system of checks to establish that you feel this is the case. I do not know what you can do and what equipment who have, but, I think the flavor of the answers is wrong.
No one can even say wheither we have to follow the envelope priniple on the ID & OD as part of our calculations, except me, I said yes, how is the CH.
Frank
RE: Positional confusion
Absolutely.
The great irony though, to check envelope requirements you will have to perform several INDEPENDENT measurements.
RE: Positional confusion
In almost every post I wish I could take back some spelling error, I get too excited to respond, quick while at work. Like the "How is that". Let's not even start with my grammar mistakes.
Frank