crown molding hanger smithline crown moulding is now a one-person job! the smithline products, patented crown moulding hanger is an easy to use, installation product for crown moulding. it is designed to make crown moulding installation easy for a single individual to do. this product was invented by a carpenter who saw the need to make crown moulding installation a one-person job. the crown moulding hanger was developed, and is produced, in canada.