Some sort of old calibrator?? Not Sure of what its for.

[aettwein]

Not sure what this is. Hopefully someone can help me out. This was made by a blacksmith many years ago and was given to my great grandfather. Since then it was passed onto to my grandfather and he is not sure of its purpose. It does have markings on it it measures up to 2 inches. it opens and closes and appears to be some sort of calibration tool, but again not sure hopefully someone can help me. Many Thanks ahead of time.

[PFSchaffner]

That's your basic caliper. Probably  no telling what exactly it was intended to measure (since they can be used for anything from dental crowns to engine mounts), unless the markings give some hint.

[wvtools]

I have owned hundreds of calipers over the years, and I have never seen one quite like it.  It was probably made for a specific unknown purpose.  Registering calipers are not super common, but not rare either.  The asymmetrical arms are quite unusual, IMO.

[turnnut]

it looks like a V notch on the right side tip ?

??? possible use:  to measure round stock when turning on a wood lathe ???

just a guess.