Question about barb threads

[CurseTheSky]

I just happened to be browsing Jab-Tech, and noticed this radiator: http://www.jab-tech.com/Swifte...20-QP-Res-pr-3975.html. It has a built-in reservoir, which is a pretty nice concept.

Anyway, the barbs are listed as "1/4" NPSM, BSPP, and G1/4 fitting (1/4" thread to 1/4", 3/8 or 1/2" barbs." If it's a 1/4" thread (and thus inner diameter), wouldn't that act like a choke (restriction) point for your entire loop? Would it defeat the purpose of getting 1/2" ID barbs and tubing?

Are all the barbs like this? This is the first time I noticed it, and I never paid much attention to the threads and ID of the threading.

 

[NinjaJedi]

Originally posted by: CurseTheSky
I just happened to be browsing Jab-Tech, and noticed this radiator: http://www.jab-tech.com/Swifte...20-QP-Res-pr-3975.html. It has a built-in reservoir, which is a pretty nice concept.

Anyway, the barbs are listed as "1/4" NPSM, BSPP, and G1/4 fitting (1/4" thread to 1/4", 3/8 or 1/2" barbs." If it's a 1/4" thread (and thus inner diameter), wouldn't that act like a choke (restriction) point for your entire loop? Would it defeat the purpose of getting 1/2" ID barbs and tubing?

Are all the barbs like this? This is the first time I noticed it, and I never paid much attention to the threads and ID of the threading.

Errr it has been a long time since I had to deal with threads. Machinist threading is different from plumbing standards but if I remember right g1/4 refers to the length of the threaded end not the diameter.

not sure if I got that right I found this out.
G = external+internal parallel

 

[NinjaJedi]

as far as I can tell G is a british standard. It refers to Parallel threads.
g 1/4" has 1/2" thread size and 19 threads per inch. It does not mean the inside diameter is 1/4"

 

[DerwenArtos12]

Yeah, thread standards are not the same as plumbing standards, 1/4"NPT an G1/4" are just different standards in thread pitch and length and have essentially nothing to do with the internal diameter of the barb.

 

[CurseTheSky]

Excellent, thanks for the info guys.

 

[aigomorla]

Originally posted by: NinjaJedi
as far as I can tell G is a british standard. It refers to Parallel threads.
g 1/4" has 1/2" thread size and 19 threads per inch. It does not mean the inside diameter is 1/4"

Bingo!

Cursed if your goig to get EK barbs on the swiftech rad, YOU NEED TO DOUBLE UP on the Oring.

The radiator will come with a set of Orings you can recycle on the EK barbs to double them up.