Bolted Flange Joints: Studs vs. Bolts

[Jack8rkin]

Hello everyone!
Please, help me with the terms.
There are bolted flange joints, right?
What if there are studs used in this joint?
Any change to the name of the joint?

Why I'm asking is because in Russian there is difference.
Stud bolts or studs are called absolutely different from bolts in Russian; hence, the change in the name.

So, please, enlightem me on that.

Thank you.

 

[PhanthomJay]

A stud bolt is a threaded rod with nuts at both ends, fully threaded or with a certain length of threads at each end and no threads in the middle, whereas a bolt has a nut at the threaded end and a fixed head at the other, not fully threaded except for the smaller lenghts. I always specify bolts, not studs, for flange connections, although either will work if they are of proper strength and designed for 'with or without threads' in shear planes. Make sure the lengths are sufficient to engage the flanges and allow for a nut and perhaps washer and locknut at the ends. Sometimes definitions get muddled, so be sure you are getting what you want, including the correct nut strength (hex or heavy hex, for example, order them with the bolts).

 

[Jack8rkin]

Thanks for the info.
I know how a bolt is different from a stud.
I'm asking about difference in terminology.
In Russia, if we use studs, the name of the joint would be шпилечно фланцевое соединение, which in translation is (don't laugh) "studded" flange joint.
In a case with bolts, it would be "болтовое фланцевое соединение", and in the internet, there are lots of links to the "bolted flange joint". Here is no question.
There is nothing about "Studded" flange joint, though.
Here is the question:
What name for the joint would you use in a case with studs in the flange joint?
Thank you

 

[AlephZero]

In British English they are both called bolted joints. I think US English is the same.

A fixing that uses a stud and a nut is sometimes called a "stud bolt" in English, to distinguish it from a stud that is screwed into a threaded hole without a nut, for example to transfer a shear force between two parts without fixing them together.

 

[PhanthomJay]

I just call them bolted flanges, and specify hi strength bolts, and always get machine bolts for flange connections. I suppose you could call it a stud bolted flange if you wanted stud bolts exclusively, but I've never used them for this app, usually just when say I need extra long lengths or full thread for multiple nuts when connecting a couple of pieces of lumber together with space in between.

 

[Jack8rkin]

Thanks a ton!
It's always a confusion when I have to translate these "studded" flange joints into English.
I've heard that studs are sometimes called "stud bolts" but never thought that the difference is in the use of nuts on them. Thank you for the explanations.

I gues the difference is like with a bolt and a screw.
If the threaded end goes through two connected parts and a nut is used to secure them, it is a bolt.
If the threaded end goes through one part and is screwed into a threaded hole in the other part to secure them together, it is a screw.
Am I right?

Sorry asking so much theory... It does not really mean a lot in practice. But you know, when I translate, it means a lot for understanding on both the sides.

 

[nvn]

Jack8rkin: In English, there is no change to the name bolted flange joint, regardless of whether the joint uses bolts or studs. I have never seen the term stud bolt, only stud. I have never seen a stud without a solid shank and a nut (that I recall); after all, there generally would be no way to tighten the joint.

If you can install a nut on the threads of a headed fastener, regardless of whether you install the nut or not, then the headed fastener is a bolt. (If someone calls this a screw, then it is a misnomer.) If you cannot install a nut on a headed fastener, then it is a screw. The distinction between a bolt and a screw is only the thread form; a nut will not fit on a screw. A bolt is called a bolt regardless of whether you install a nut or install the bolt into a tapped hole.

 

[Jack8rkin]

Thank you for your opinion.
But concerning the below:

nvn: "The distinction between a bolt and a screw is only the thread form..."

I got a confusion here. Other sources like ASME and WIKI contradict you.
How about this?
http://en.wikipedia.org/wiki/Screw

See: Differentiation between bolt and screw

However, in Russia some people say exactly what you wrote in the above message.
So, I guess, definitions may differ.
Besides, for types of screws we have at least 3 terms:
винт (screw that has threads upon which a nut could be screwed); шуруп (pointed screw that is not fully threaded and is usually used with wood); саморез (the same as the previous one but fully threaded and also could be used for other applications other than woodwork).

 

[nvn]

I got a confusion here. Other sources like ASME and WIKI contradict you.

Jack8rkin: Yes, those sources contain misnomers, which I parenthetically alluded to in post 7. Misnomers are illogical, and can simply be ignored.

 

[AlephZero]

I have never seen the term stud bolt, only stud. I have never seen a stud without a solid shank and a nut (that I recall); after all, there generally would be no way to tighten the joint.

The are other ways to fix the parts with studs, for example adhesives or a shirink fit. The main function of the studs might be only to locate the positions of the parts accurately, not to fix them. The fixing might be some type of clamp which does not give accurate location.

I got a confusion here. Other sources like ASME and WIKI contradict you.
How about this?
http://en.wikipedia.org/wiki/Screw

Part of the problem (as the wiki page says) is that the English word "bolt" was used for hundreds of years before there was any technology to cut accurate screw threads, and some of those uses still exist in non-technical English, for example "door bolts" where the simplest type was (and still is) just a sliding bar, without any thread.

If you use the ASME definition, at least you can give a good reference to justify it, and people who disagree should be arguing with ASME, not with you

If you are translating, it might be easier to use the neutral word "fasteners", whcih includes both scews and bolts.

 

[Jack8rkin]

Thanks a ton to everyone.
AlephZero: "If you are translating, it might be easier to use the neutral word "fasteners", whcih includes both scews and bolts."
Usually when I translate it's a specific thing like a bolt or a stud. My specific question was about the "studded" flange joints. I guess I have gotten an answer here.

But still, if we speak about a heat exchanger shell and head. The joint between them might use a gasket, studs and washers and nuts.

If in Russian the joint is called "studded" flange joint, and I translate it (properly) bolted flange joint (because as you say there is no difference in English), and you see studs instead of bolts in the drawing -- won't it all couse confusion?

 

[Jack8rkin]

Jack8rkin: Yes, those sources contain misnomers, which I parenthetically alluded to in post 7. Misnomers are illogical, and can simply be ignored.

I looked through ASME B18.12 Glossary of Terms for Mechanical Fasteners.
Very simillar to what is given in WIKI.
So ASME is nothing to you? It is not an authority at all in the U.S. and can be avoided?
What standards do you use?
BTW, if I do what you say with our Russian GOST, I will be probably fired.

 

[nvn]

Jack8rkin: My apologies, because my phrase was unclear. Let me rephrase it. Misnomers are illogical, and sometimes can be ignored.

Offhand, I currently cannot recall a standard that contains a correct definition of bolt, and screw, in English. I admire your desire to make sense out of misnomers, and illogical or ambiguous definitions. I hope my reply in post 7 is helpful.

 

[Jack8rkin]

Offhand, I currently cannot recall a standard that contains a correct definition of bolt, and screw, in English. I admire your desire to make sense out of misnomers, and illogical or ambiguous definitions. I hope my reply in post 7 is helpful.

Correct from whose point of view? Yours?
Do you want to say that standards are for those who wrote them and everyone else uses other definitions?
Or the ASME definitions are incorrect because they do not mathch your (read everybody elses's) definition that you gave in post 7?

I do not see ASME definitions as illogical. There is definitely sense in them.
There may be different approaches to how to define things.
The matter here, as I see it, is whether or not the definition is accepted by a society.
So, what you wanted to say is that ASME defines the bolt and screw wrongfully the same as each and every standard in English?
And what the standards say is not accepted in the U.S.?
Or, maybe their definitions are new and still not accepted by people who use them?