Cutting tool for processing nut of sliding screw device and method for processing nut of sliding screw device

A method for processing a nut of a sliding screw device, at least comprising the steps of:

• processing a material of the nut to form a prepared hole;
• forming a thread at an inner peripheral surface of the nut by inserting a nut processing cutting tool into the prepared hole by relative rotation of the nut processing cutting tool;
• and
• hardening the inner peripheral surface formed with the thread, wherein
• the material of the nut is aluminum,
• the nut processing cutting tool includes, at an outer peripheral surface of a cylindrical cutter, a recessed groove which has an arc-shaped cross section, which extends in a helical pattern, and whose bottom portion has a diameter larger than a diameter of the prepared hole,
• in the step of forming the thread, a ridge portion of the thread is formed by cutting by the recessed groove, the ridge portion having an arc-shaped cross section and extending in a helical pattern, and
• in the step of hardening, an anodic oxide coating is formed on the inner peripheral surface.