Whats it for?

[john k]

Here is a tool, rather, a holder or fixture.  It is mostly all cast iron, about a foot long.  Has holes for screwing down to a table.  The base has a concave place for centering the work piece.  I"m guessing it would compress a spring, with that slot in the bar to allow a large wingnut to be tightened.  But just what?   Not mine, a fellow brought it by work for me to guess its usage, he got it on a farm sale.  No dates, patents, or names cast into it. 

[Falcon]

Looks like it is used for repairing inner tubes, the Spock -or- vulcanizing method maybe.

[Papaw]

Might be for leatherwork. It could hold these tools-