Petcock sizes

[chopit25]

I was looking for petcocks for different tanks and they have sizes like 1/4, 3/8, 22mm and others. I have an old sporty tank and a paughco mustang tank that both use what I thought was a 3/8 npt. Well I ordered a 3/8 npt elbow and a 3/8 npt petcock and that is not what I have in my tanks. The one I need to fit my tanks is a much smaller size.

The petcock on the right is the correct size that I need but is broken. I want to get a petcock but am afraid I will order the wrong size again. It has to be a standard size as two of my tanks use it. So what size should I actually be looking for?

 

[gggGary]

looks like 1/4" NPT from here, go to the local plumbing aisle take it along and try it on some 1/4" iron pipe fittings there.

The 1/4" comes from the ID of the pipe not the thread size but only a plumber would know that.

 

[chopit25]

looks like 1/4" NPT from here, go to the local plumbing aisle take it along and try it on some 1/4" iron pipe fittings there.

The 1/4" comes from the ID of the pipe not the thread size but only a plumber would know that.

Ok thanks gggGary.

 

[weaselbeak]

You need a 1/4 inch thread. I use a pair on my tank that are 1/8 NPT and the thread is fairly fine looking. One of them would not drop enough gas by itself, so I used 2. The brass above is 3/8.

 

[chopit25]

Thanks guys. I am having trouble finding a 1/4 npt male to a 3/8 npt female 90* elbow. I am not sure this exists? Lol
For now I have a 1/4 npt street elbow to a 1/4 to 3/8 adapter to a 3/8 petcock. I would like to have an elbow that was 1/4 to 3/8 to minimize connections and shorten the length a little. Any ideas where to find that elbow?

 

[ridgerunner1965]

i believe the elbow that you are looking for is called a street L. male on one end and female on the other.ive not seen a lot of them that small. good luck!