Thread Gage Problems

[Tinyfxds]

We had some parts returned from a customer who said the threads didn't pass inspection.  They stated that the NO GO went in two full turns before it snugged up.  It's a  8-32 unc thread with no special call out on the print as far as class of fit.  So what is the standard for a No Go gage?  I was told that, after 3 full turns the thread is suspect, and should be marked.  I never actually saw an ASME or ISO standard for thread gages relating to this situation.  I have to believe there is something out there.

 

The machinery handbook says "Not less than 3 full threads must remain on any "Not Go" plug.  If I'm understanding that correctly, it means that you should be able to turn a No Go gage into the hole and as long as 3 full threads are sticking out, it's still a good thread.  ???

[Guest]

This is one that many people claim this is a standard or that is a standard

 

As far as I know, there is no standard for how many turns a "no go" gage can go in.......

 

I have seen companies that will accept a full turn and others that if the "no go" goes at all the part is no good.

 

The only standards you seem to find are company standards for acceptance/rejection

[Joe788]

Send the parts back to the customer.

 

http://www.threadcheck.com/no-go-gaging-per-ansi-asme-b1.2-1983-an-american-national-standard/technicalinfo/

 

 

As Stated in ANSI/ASME B1.2-1983, the “NoGo (Hi) functional diameter is acceptable when the NoGo (Hi) thread plug gage applied to the product internal thread does not pass over the thread more than three complete turns.”

[Guest]

Send the parts back to the customer.

 

http://www.threadcheck.com/no-go-gaging-per-ansi-asme-b1.2-1983-an-american-national-standard/technicalinfo/

Thanks Joe, I have never seen that one before

[Tinyfxds]

Thank you sir.  That is exactly what I was looking for

 

Send the parts back to the customer.

 

http://www.threadcheck.com/no-go-gaging-per-ansi-asme-b1.2-1983-an-american-national-standard/technicalinfo/

[Del.]

Send the parts back to the customer.

 

http://www.threadcheck.com/no-go-gaging-per-ansi-asme-b1.2-1983-an-american-national-standard/technicalinfo/

That's good info. So a no go plug gage is allowed to go into the threaded hole up to 3 turns that allows for wear on the gage. Is that right?