Abstract: An adjustable locking device facilitates the insertion and removal of a diaphragm upper half in the upper portion of the split housing of an axial turbine. The diaphragm upper half is provided with a slot at its outer edge which permits the turbine housing locking pin to pass therethrough. An eccentric pivot locking device positioned in the slot is rotated to close the slot and secure the diaphragm half in the turbine housing relative to the pin. Slots may be provided at both edges of the diaphragm half or at only one edge while the other edge contains a bore hole recess to receive a corresponding locking pin of the housing. Set screw means associated with the locking device may be provided for further security.