Stud bolt lengths

[OldmanHaggler]

Hello,

Does anyone know how to calculate
for 26” to 60” flange bolting, Stud bolt lengths?.

Is there a standard formula to figure it out?

I have been using this:

Stud length = (flg thk x 2) + (gasket) + (stud dia. X 2 ¼)

I think my studs are a bit short. I don’t think I like that Idea.

Any help would be great,

Thanks,

 

[JJPellin]

My table of stud lengths would correspond to a recommended length as follows:

Stud length = (flg thk x 2) + (gasket) + (stud dia. X 2) + 0.375

For a 30" 300# RF flange, your formula would call for a stud length of 11-5/16". My table would call for 11-1/4". Yours doesn't seem too short to me.

Keep in mind, the flange thickness must include the height of the raised face. And the gasket thickness must be the compressed thickness (the thickness of the metal ring). The studs must have a full nut of engagement at both nuts. But extra stud sticking out of the nuts will just give you trouble when you try to remove the nuts.


Johnny Pellin

 

[OldmanHaggler]

Thanks for the help!

 

[dvd]

...you know along the same line, a friend of mine in the horse business was breeding her apaloosa mares to shetland stallions. She came to the conclusion that her studs were too short also, and nut removal was still difficult.

Sorry, my muse whispered that in my ear.

 

[MJCronin]

Oldman..

You could always use this reference:

http://www.awhem.org/PDFs/TR9501A.pdf

No charge.....

-MJC

 

[OldmanHaggler]

Thanks a bunch for all the help guys!

 

[rconner]

In my opinion required "stud length" could be defined by the intended, specific intended use of the stud. If the stud is to be threaded into a tapped hole e.g. in a wall pipe previously embedded flush into a concrete wall, or into some tapped holes in a valve face, I think the stud might well be specified/ordered to be basically the same "length" as a bolt (shank) that might otherwise be inserted with clearance through both mating/drilled flange holes. If on the other hand a stud is to be used with "double-nuts", to in effect simulate a bolt often used to compress the gasket etc. for many common flanged joints, the stud would normally be ordered accordingly longer (to allow engagement length for a second nut).

 

[Cockroach]

It is also called out in the pipe/flange codes! I've noted a few in this forum, Ring specifications, where the stud lengths are called out for the various flanges.

Kenneth J Hueston, PEng
Principal
Sturni-Hueston Engineering Inc
Edmonton, Alberta Canada

 

[noideaqq]

Does this exist too for European flanges where bolts and nuts are used?

 

[proinwv2]

Many users insist on seeing one or more threads beyond the nut. This ensures them of full thread engagement in the nut.

Paul Ostand

http://www.ostand.com

 

[ytse]

Please check Annex C (Method for calculation of bolt length) of ASME B16.47 (Large Diameter Steel Flanges NPS 26 through NPS 60).