Threaded Things for Dummies

National Pipe Thread (NPT)

Want to catch phony experts at their game? It's really not that hard: all you need to do is ask them a question that has no real answer and watch as they spin furiously trying to impress you with the weight of their "knowledge." Say, ask someone what is the difference between the Celsius and Centigrade temperature scales, sit back and enjoy. Well, we caught one of those phonies a while back and today's her day: it's eHow.com contributor Andrea Stein (she's already won the DotD award; not once but twice). We ran across Andrea attempting to tell people "What is the Difference Between Pipe Thread and Conduit Thread" at the mother site (now at HomeSteady.com), and boy, did she thrash around for a while.

First, Andrea "explained" what threads are in the world of pipes and tools:

"Thread refers to an internal ridge, or helical structure, used to convert between rotational movement, or allow an external (male) thread, or outer thread diameter, to rotate along the axis of an internal (female) thread to fasten them together."

All we have to say to that "explanation" is "Whaaaa? That just makes no friggin' sense!" But, as always, there's more. Andrea goes on to (mis)inform her readers that "Pipe threads and conduit threads enable fittings to join together, but vary in design [emphasis ours]." Spoiler alert: someone from Battle Creek Electric – the kind of person who probably knows something from real-world exposure – informs Andrea (in a comment) that  "Actually electrical conduit and plumber's pipe has [sic] the same thread. They are both National Pipe Thread."

We guess they don't teach that sort of stuff to English majors. Not to be deterred, Andrea went on to tell us all about how the two are different:

"Pipe thread refers to a helical, or spiral shaped ridge, located at one end, or both ends, of a pipe that enables two pipes to join together. Conduit thread refers to a helical ridge located at one end of a pipe that tapers, or is designed with a narrower cut end."

No, Andrea, both have threads at one or both ends, and both taper. Stein also tells her readers that

"Pipe threads, commonly used in high pressure pipe lines in industrial systems, are also utilized in plumbing applications. Plumbers, when using pipe threads, apply sealing compounds to the joints for added leak protection. Conduit threads are designed for use in liquid distribution piping systems because of their ability to form a wet seal."

Conduit is used "in liquid distribution piping systems"? Really? By this time Andrea is clearly throwing bull at the wall to see what sticks, as she exposes her total lack of knowledge on the subjects of threads, pipes and conduits. Small wonder we're giving her the Dumbass of the Day award – but more to the point: why, when someone knowledgeable has already pointed out the error, does eHow.com let this garbage stand? One never knows...

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