What Is This?

I've had this for several years, sort of a barn find but I have no clue what it is.. I think it's some kind of engraving tool? Bic for scale..

 

This is a leather scoring tool called a swivel knife.

 

That explains a lot.. in the same box was a bunch of other stuff that I had identified as leather working tools.. Thanks!

 

You can put a finger or two in the U area and grip the knurled area with your thumb and fingers. Usually drawn toward you.

 

This was the other stuff I mentioned.. Maybe some day I'll give it a whirl..