SpudFiles

Been doing a little research and realize I can use AN-12 threads over and over again and they never wear out when the 3/4" NPT are only good a few times then you have to toss them. I also am told I don't have to use teflon tape when using the AN-12 threads.

Pro's and cons ?

My project will only see 200PSI at the most.

What are your thoughts ?

I'm really not sure. I've never heard that. I only use npt and I use them all over and over. I think you'd still need Teflon...

I'm not familiar with "AN" threads. Did you mean UNF-12or UNC-12?

velocity3x wrote:I'm not familiar with "AN" threads. Did you mean UNF-12or UNC-12?

http://en.wikipedia.org/wiki/AN_thread

velocity3x wrote:I'm not familiar with "AN" threads. Did you mean UNF-12or UNC-12?

AN stands for Army Navy.
If you look at Nitrus oxide connectors on race cars it's what they use to hold 1000PSI or more. Usually they are anadized Aluminum, either Black, Blue or Red. The connectors are just very flexible compared to NPT threadings.

I think that NPT are better becasue they are easier to find... it really is not that difficult to seal a joint so I don't think it makes any sense

There are different techniques that can be used with NPT/BSP threads if you want to seal them without using teflon tape or loctite...

this method won't work with all fittings... only those that have a sort of lip where you can place an o-ring and then as you screw in the other fitting a seal is formed between the lip, the o-ring and the surface of the other fitting

AN threads are not intended to be leak tight anymore than a screw at the hardware store is intended to be such. The threads just correspond to the fittings.... Which are compression fittings.

HOWEVER, the standard AN fitting is a pretty trick deal. It "just happens" to be compatible with SAE hydraulic fittings. So, if you have an AN fitting and an SAE fitting, all you need is an O-ring and you'll have a nice joint good to several thousand PSI.

Also note that "AN" fittings are increasingly hard to find if you look for them as such. Why? Because private industry decided that they were way cool and co-opted them. But of course, industry could never call them "AN" fittings.... Translation? Look for a "JIC-37" fitting. It's an "AN" fitting with current nomenclature.

Personally? If AN fittings were cheap and ubiquitous, I'd use 'em for everything. But they aren't. So I stick with whatever is cheapest, most available, and up to the task. Often that's NPT or NPTF, but obviously not always.
(Yes, I deal with "AN-based" hydraulic systems on a daily basis)

Thanks that was exactly what I needed.