Hi all. Used to be in the tool room myself many years ago. I have not seen one of these before but would hazard a guess that they were used to sharpen something like milling machine slitting discs. Looks like they would be mounted on the middle mandrill which I assume is something like 1" and then the table would be rotated to the desired angle and then the tool sharpened. I think the upright bar is used as a stop against one of the slitting disc teeth. Sorry can't help with a manufacturer though.