Abstract: A plate cylinder has a shaft end portion that is rotatably supported in a press frame for axial movement relative thereto. A gear hub is axially movable and coaxially positioned on the shaft end portion. A helical driven gear is coaxially positioned on and non-rotatably secured to the gear hub. The teeth of the driven gear mesh with the helical gear teeth of a drive gear fixed relative to the driven gear. A circumferential adjustment housing is rotatably secured to the gear hub to permit rotation of the gear hub relative to the housing. The housing is non-rotatably positioned for axial movement in a support frame that extends outwardly from the press frame. Resilient members retained within the circumferential adjustment housing urge the housing to move axially relative to the support frame. A circumferential adjustment mechanism is non-rotatably secured to the circumferential adjustment housing and axially moves the housing toward and away from the main frame.