I worked on a job recently where we installing a multipoint lube system using 3/4 black steel pipe from a central supply tank to each work station. The 20 ft. pipe lengths supplied were glossy black and not threaded on the ends. After about 20 thread cuts the RIDGID rental power pipecutter's dies were shot and we had to resort to a new RIDGID hand die set. Yes the power cutter had it's own lube oil system and we used RapidTap with the hand dies. The hand dies were not doing much better on that pipe either, short chips rather than curls of metal coming off the dies. The company supplied no documentation on the pipe, it looked like regular schedule 40 black pipe but I think this stuff may have been a 'structural' grade of pipe, intended for welding, not tapping. It was in @ 20 ft lengths, not threaded on the ends and had a VERY SHINY scale, black pipe I've used before was threaded on the ends and had a dull black scale.
When we were working with it I began to call it Indian Ocean Shipbreakers pipe,
Does black pipe come in a "threadable" as well as "non threadable" grades and is the "threadable" always threaded on the ends?