Shows for air hammer/chipping hammer cylinder. Groove for retaining ring for quick release collar.Found this. What's it go to though.
Edit: the link does work...
Yes, it is a pen style scribe.Looks like a Retractable point scribe.
I've see fixed point versions with a Soap stone round kept in the other end by a collet and twist ring.
Sure enough.....there's gobs of em on ebay.View attachment 489185
Chain break for old detachable chain. Think of the stuff before roller chain. Chain fits in the slots and you drive it apart to remove or add links. Probably more of a wall hanger type thing nowadays.




