Re: Thread Gage - No-Go end - No-Go end is allowed to enter the part up to 1.5 turns
Get me a consensus of what you want the thread title to be... How about "ANSI Unified thread plug gage - How many turns allowed for no-go end?" (Confirm we refer to ANSI Unified thread?) There is a Standard ANSI B 1.2. My 23rd edition of Machinery's Handbook says...
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 idiosyncrasies.