Machining tool

An attrition liner machining tool, configured to machine a surface of an attrition liner provided radially outward of a set of a plurality of fan blades in a gas turbine engine, the attrition liner machining tool comprising:

• at least one rotating machine tool having a first end and a second end, the second end being opposite the first end;
• a connector at the first end of the at least one rotating machine tool;
• a cutter at the second end of the at least one rotating machine tool;
• a counter-weight having a second connector configured to rigidly connect to the rotating fan blade mount of the gas turbine engine and having a mass selected to balance a mass of the at least one rotating machine tool when mounted to the rotating fan blade mount;
• a support frame, configured to be rigidly connected to the rotating fan blade mount of the gas turbine engine and to support the rotating machine tool and the counter-weight or a first and second rotating machine tool in respective locations on the rotating fan blade mount;
• a base frame, configured to be mounted to the gas turbine engine in a fixed position relative to the attrition liner;
• and
• a motor system, configured to rotate the support frame relative to the base frame,
• wherein the connector is configured to rigidly connect to a rotating fan blade mount of the gas turbine engine that, in use of the gas turbine engine, supports the fan blades, the connector being configured to fit a complementary connector in the rotating fan blade mount that, in use of the gas turbine engine, is configured to securely receive a connector of a fan blade;
• the cutter is configured to machine the attrition liner;
• and
• the at least one rotating machine tool is configured such that, when it is connected to said rotating fan blade mount of the gas turbine engine, the cutter is passed across the surface of the attrition liner when said rotating fan blade mount is rotated.