Re: Thread Gage - No-Go end - No-Go end is allowed to enter the part up to 1.5 turns
Absolutely, Wayne! I'm old, semi-retired and rarely have need for a more recent version when many things are available via internet. I think I may have some editions in boxes in the garage which go back to the 60's and 70's! Hence my mention of WHICH edition!
The operative phrasing throughout the years has always been some version of "use common sense! If you have only 2 threads in a thin sheet metal panel, reference to three threads is invalid."
The current edition of the Machinery’s Handbook is the 27th. How old is that 23rd edition?
As for the standard being discussed, yes, one gaging requirement for the Unified Thread is specified in ANSI B1.2, but the gaging requirement is also specified in BS 919; JIS B 0255; JIS B 0256; SAA AS 3635; and an ISO standard that I can not identify at the moment. Then there is a similar list of requirements for NPT, NPTF, ANPT, BSPP, BSPT, ACME, Buttress, Metric, Whitworth, Trapezoidal and other threads.
Use requirements for thread gages vary based on the standard that defines them. When a part is designed, the standard requirements for the threads should be stated on the print. Gray areas in the standard, if critical, need to be further defined on the print. I believe that, if you check the wording in the ANSI B1.2, for example, you will find wording defining the use of the NOGO gage which states something to the effect of: Shall not enter the part not more than 1-1/2 to 3 turns, unless otherwise specified by the customer. This wording covers short parts or long parts or specific product requirements not obvious to the maker of the component part, as long as engineers fully define the component requirements, and quality professionals review the standards for their specific idiosyncrasy.
As for the standard being discussed, yes, one gaging requirement for the Unified Thread is specified in ANSI B1.2, but the gaging requirement is also specified in BS 919; JIS B 0255; JIS B 0256; SAA AS 3635; and an ISO standard that I can not identify at the moment. Then there is a similar list of requirements for NPT, NPTF, ANPT, BSPP, BSPT, ACME, Buttress, Metric, Whitworth, Trapezoidal and other threads.
Use requirements for thread gages vary based on the standard that defines them. When a part is designed, the standard requirements for the threads should be stated on the print. Gray areas in the standard, if critical, need to be further defined on the print. I believe that, if you check the wording in the ANSI B1.2, for example, you will find wording defining the use of the NOGO gage which states something to the effect of: Shall not enter the part not more than 1-1/2 to 3 turns, unless otherwise specified by the customer. This wording covers short parts or long parts or specific product requirements not obvious to the maker of the component part, as long as engineers fully define the component requirements, and quality professionals review the standards for their specific idiosyncrasy.
The operative phrasing throughout the years has always been some version of "use common sense! If you have only 2 threads in a thin sheet metal panel, reference to three threads is invalid."
I don't intend to offend, I just have never learned how to be socially appropriate.