Casing cutter tool and method for operating the casing cutter - pressure actuated piston sleeve actuating ball valve

The invention is a drill pipe string (10) - conveyed casing cutter tool comprising - a cylindrical main body (0) with casing cutter knife arms (3) rotatable on pivot axles (31) and provided with rotating cogs (32) in a first end of said knife arms (3), said knife arms (3) retractable into recesses (01) in said main body (0), - a spring (2) - loaded piston sleeve (4) with central bore (40) axially arranged in the main body (0), - said cogs (32) engaged with a corresponding linear cog array (41) on said piston sleeve (4) and arranged for extending said knife arms (0) with a cutting edge (33) out of said recess (01). - The piston sleeve (4) is provided with a ball valve (6), - said ball valve (6) is actuated by a translation of a piston sleeve (4) controlled by a control module (1) so as for shutting said central bore (40), - so as for when pressure is set from surface through said drill pipe string (10) and said ball valve thus is closed, said piston will move and actuate said knife arms (3) to a cutting position, for rotation cutting an inner wall of a casing when said drill pipe string (10) is rotated.