Unified 'MOD' screw thread?

[leccles]

Hello all,

I have a drawing that refers to a UN-2A MOD thread.

Can anyone explain to me the implications of the MOD suffix?

The drawing details the limits of the major, pitch and minor diameters etc.

Regards,

Lee

 

[KENAT]

See ASME B1.1-2003 section 6.7."Method of Designating Threads Having Modified Crests"

Essentially as I understand it the same pitch diameter as the standard thread but with modified major diameter (screw) or modified minor diamter (nut).

However, unless a UNS with modified crests I'm not sure why the pitch diameter is given.

KENAT,

Have you reminded yourself of faq731-376 recently, or taken a look at posting policies:

http://eng-tips.com/market.cfm?

What is Engineering anyway: faq1088-1484

 

[hydtools]

It means the thread is not 'standard' and the thread dimensions noted must be used rather than relying on standard dimensions.

Ted

 

[leccles]

Thanks for the prompt respsonses, everyone.

Lee.