This 3/8", 18TPI Die was given to me by a friend, cleaning out an old shed.
The only markings on it are " 3/8, R, W". I have never come across a die constructed in this manner before.
Can anyone shed some light on this item please.

New to me. Can't tell if it's riveted or bolted but either way I've never seen anything even close to that.

It is for pipe or conduit threads, 3/8-16 & 3/8-24 are standard bolt sizes.

The construction of that die is very unique. Four thread-cutting inserts, held in place by two stamped plates of steel riveted together. I've never seen anything like it before.

The front and rear plates are riveted together.

Quote from: Plyerman on January 03, 2018, 05:06:49 PM
The construction of that die is very unique. Four thread-cutting inserts, held in place by two stamped plates of steel riveted together. I've never seen anything like it before.

+1