Abstract: Notches are placed between adjacent shroud portions of integrally shrouded rotating blades of a steam turbine forming a turbine rotor blade row generally 90.degree. apart and a predetermined wedging force is applied to each notch to wedge adjacent shroud segments apart, the width of the gap formed is measured, recorded and compared with future measurements made after the turbine has been in service to determine wear on the shroud portions; also, a wedging force is applied to open a gap at each notch to receive a predetermined sized shim, the wedging force is relieved clamping the shim in the gap and then generally increased until the shim can be pulled from the gap by hand, the wedging force at which the shim can be pulled is recorded and compared with future similar recordings after the rotor has been in service to provide an indication of wear on the shroud portions.

Abstract: A lathe for machining a balloon-shaped pocket in a turbine rotor comprising a carriage disposed on ways to move axially along the bed of the lathe, a cross-feed mounted on the carriage, the cross-feed moving toward and away from the axis of the lathe and a tear-dropped shaped tool holder for holding a single-edged cutting tool disposed on the cross-feed in such a manner that the cutting tip of the single-edge tool moves in a circular arc and cooperates with the cross-feed to cut a balloon-shaped pocket in a turbine rotor.