Thread gage marking 2A and 2B 1

[SeasonLee]

Hi All

A simple question, would like to know your comments before I contact with the gage maker.

For the thread gage 1/4-28 UNF-2B, I know 2B means internal fit, 2A means external fit, I can not realize why 2A and 2B marked on the same gage, please ref to the attached for details.

Thanks for your inputs

Season

 

[ctopher]

Looks like a typo

Chris, CSWA
SolidWorks 14
ctopher's home
SolidWorks Legion

 

[MintJulep]

It's a plug gage. For use in checking an internal thread presumably. As you already know, an internal thread is designated by "B".

Typically a double-ended gage like that would have a "GO" and a "NO-GO" end (with the NO-GO end often colored red.

So to me it looks like a typo - but on the gage itself. The packaging appears correct.

 

[Tunalover]

The -2B marking on the gauge may mean that the gauge is intended to be used to inspect an internal thread.


Tunalover

 

[tbuelna]

It should be fairly obvious that an externally threaded go-no go gauge is intended to be used for checking internal threads. Otherwise how would you use a gauge with external threads to inspect parts also having external threads? The C-of-C provided with the gauge only states that the gauge has been inspected in accordance with applicable standards. And the markings on the gauge clearly indicate it is intended for inspecting a 1/4-28 UNF-2B thread. So you have no reason to gripe with the vendor except to ask for a suitable replacement gauge, which I'm sure they will be happy to provide.