Picked up a crate full of tools yesterday at a yard sale. Has some great stuff in it, most is quite old. A lot of sockets, engine building tools, wrenches, and some odd stuff. In the pile was this thing I can not identify. Everything else i am sorting and cleaning right now.

 

Crimping die.

 

Thank you, i havent the slightest clue what to use it on, but now i can look it up.

 

It appears to be a crimping die. Normally there would be an O-ring around the groove in the middle to hold it together.

 

I thought it was part of a tail pipe expander

 

I think it's a Swage Tool.
Put a bolt through it and tighten it up, and see if it doesn't swell up.

 

it is a well used tail pipe expander missing the through bolt and washers