Pipe fitting/plug chart

[C Body Bob]

Often referred to as NPT fittings. This stands for National Pipe Thread. There is also National Course (threads widely spaced such as head bolts) & National Fine Thread which is tightly spaced threads such as interior bolts & trim bolts. NPT is commonly found around fluid plumbing such as fuel line & water pump fittings etc

 

[live4theking]

NPT are tapered threads unlike nuts and bolts. Something else to note is that black and brass cannot be interchanged with galvanized fittings. At least that's what I've been told.