Are there smaller neck size steels than 3/4”?

[rvojr]

Are there other Hp/LP steel tank neck sizes other than 7/8” and 3/4” ? I was asking about a twinset, but was told the neck was smaller than another 3/4”. It was from 2002. I’m going to get some pictures of the stamping son the neck but was wondering if anyone has seen smaller neck sizes. Thanks for any insight you can provide!

 

[Whitrzac]

The 7/8 ones are physically smaller than the 3/4 ones. Different type of thread and method of measuring IIRC

 

[rvojr]

Twinset on left

 

[rvojr]

I looked back at advice from Tbone previously and I need the other numbers prior to this view.

 

[broncobowsher]

So you are looking at the outside diameter of the neck and not the threads themselves?

 

[Andy in Gap]

Old steel 72s have the 1/2” tapered threads. These are the only 3 types in common usage that I know of.

 

[rvojr]

So you are looking at the outside diameter of the neck and not the threads themselves?

Correct. I was looking to purchase since they were near to me.

 

[Gone for diving]

3/4 thread you refer to measures closer to 1 inch. Its similar to NPT only not tapered, its straight, Can not go by measurements for this thread, there is different names for it, Mechanical straight pipe is one, NPTS

The 7/8 thread is a true 7/8 on the outside of the Male thread, but is also a straight thread,

1/2 npt is tapered and will measure closer to 3/4inch,

 

[Gone for diving]

As far as I know sounds like it's the 7/8 thread, 2002 tank highly unlikely to have pipe thread, and if it did you more than likely will see a few threads passed the top of the tank,

 

[captain]

Bolt threads and pipe threads are measured differently, Pipe is measured by inner diameter so the thread which is on the outside is larger than the stated size of the pipe. Bolts are measured by outer diameter and more closely represent the actual diameter of the thread.