Rotor tip clearance

A method of setting a clearance between a rotor and a stator of a rotor assembly for a turbine engine, the rotor assembly having a plurality of rotor-to-stator stages, the stator having a nominal centerline, wherein the rotor assembly comprises either;

• the rotor assembly having the rotor including an array of radially extending blades and the stator including a casing and the clearance is defined between the blades and the casing, or
• the rotor assembly having the rotor including a rotor drum and the stator having an array of radially extending stator vanes and the clearance is defined between the rotor drum and the stator vanes, wherein the method comprising:
• (i) correlating in-service rotor-to-stator rub patterns for a rotor-to-stator stage of a number of turbine engines,
• (ii) setting a position of a machining centerline relative to the nominal centerline of the stator, the position being towards a heavy rub,
• (iii) machining the stator about the machining centerline,
• (iv) repeating steps (i) to (iii) for each rotor-to-stator stage of the plurality of the rotor-to-stator stages,
• wherein the machined stator having been formed by at least two machining steps at different axial positions having different center-lines.