I have heard the steel 'thread protectors' called merchant couplings but I do not know what they are used for. Most I have seen have ended up in land fills. Now I am curious why they are included. Typical #150 couplings used for plumbing are cast and have a raised band on each end in addition to the threads not going all the way through.I have also heard IPS called NPS, Nominal . . . Goes with NPT??
Redsy,
There are also dies for plastic pipes and coated pipes.
Phil H
