My Schramm parts book for theModel 60 compressor lists the following;
FUE-731 Fan Assy. (51-8600-C17) The Ford # is a 1936 truck fan,6 blade,17"
It also lists the following;
FUE-731-C Blade, this is a Schramm p/n
A fellow by the name Frank McBride in Fort Worth,Tx. had all the old Schramm parts stock. Don't know if he is still living or has the parts any more. Worth a try. Phone #was (817) 370-2039