A roll forming apparatus includes at least one convertible roller assembly. The convertible roller assembly includes a support plate rotatably mounted on a shaft. The support plate includes at least one roller. The support plate may be toggled by an actuator from a first position for forming C shaped members to a second position for forming Z shaped members.
Disclosed is a roll-forming machine formed of a machine base and pairs of forming roll sets for the formation of a C-shaped component or a Z-shaped component from a sheet material, the two forming roll sets of each pair being symmetrically disposed at left and right sides on the machine base such that a gap is defined between the two impression wheels and two sheet-transfer wheels of each pair of forming roll sets for easy performance of maintenance work. The shaft-forming wheels of the forming roll sets of the 1.sup.st and 4.sup.th pairs are mounted with a respective locating block for easy rotation through 180.degree. between two positions and selectively locking in one of the two positions by a respective locating rod to set the roll-forming machine for processing C-shaped component or Z-shaped component.