I just picked up a used protractor for a combination square.  I thought it would fit on my stanley square, but while the blade fits into the head it will not lock in place.  It seems as though it would take a blade (rule) that is 1.125″ wide rather than the standard 1″ wide blade.  I can just make out “The L. S. S. Co Anthol MA No 490 stamped on the edge of the base. 

 I can’t seem to find 1.125″ wide replacement rules anywhere on line.  Is the protractor broken (seems not) or does it take a vintage blade that was wider?  Any idea where I can find a replacement rule for this protractor head?