A press assembly for pressurizing a body, comprising a frame and a cartridge for applying load to the body, in which the frame comprises a bore for accommodating the cartridge. The press assembly further comprises an axial securement mechanism for securing the cartridge axially within the bore and a radial securement mechanism for securing the cartridge radially within the bore. The press assembly is configured such that the cartridge can be rotated in the bore between a locked condition and an unlocked condition. The radial and axial securement mechanisms are cooperatively configured with respect to each other so when the cartridge is in the locked condition, both the radial and axial securement mechanisms are engaged and when the cartridge is in the unlocked condition the radial and axial securement mechanisms are both disengaged and there is a clearance gap between the cartridge and the bore permitting the cartridge to be axially displaceable within the bore.