Abstract: A bladed rotor assembly for a turbomachine includes a hub having a circumferential blade retaining groove and a plurality of blades which have rhombic shaped platforms. The blade retaining groove is continuous and the blades are loaded into the groove by inserting them with the generally axially directed faces of the platforms directed circumferentially. Each blade is then turned to its final operating position when the axially directed faces are axially directed and then further turned to reduce the amount of room the blade platform takes up in the circumferential direction to allow enough room for all the blades to be loaded. After all the blades are in the groove they are all turned finally to their operating positions and locked in place. A method for assembling a turbomachine rotor assembly is disclosed, also.