9" Fairmount adjustable

[oldgoaly]

This was rusty & stuck. After some quality time in the molasses bath, then rinsed with water then sloshed around in a weak phosphoric acid bath to  stop the  flash rusting. I was about to put it in the  noname wrench drawer but I spied some lettering. About 2 minutes on the wire wheel it came out nice. Last pic is  after a spray of semi-gloss clear finish. Almost looks like new!   Anyone know what the  45 stamped in the lower jaw means?