Machine tool having a rotary table

A machine tool comprising:

• a rotary table for attaching a workpiece;
• a motor for driving the rotary table;
• a clamping mechanism for clamping rotation of the rotary table;
• and
• a timer for setting a time taken until a subsequent command is made available after an unclamping command for releasing a clamping operation of the clamping mechanism to a set time,
• wherein the machine tool includes
• a load measurement unit for measuring a load of an output shaft of the motor,
• a reference load storage unit for storing a reference load of the rotary table in advance,
• a provisional load storage unit for measuring and storing, as a provisional load, a load obtained when an unclamping command of the rotary table is output and the rotary table is rotated after the set time set in the timer passes,
• a load comparison unit for comparing the provisional load stored in the provisional load storage unit with the reference load stored in the reference load storage unit, and
• a timer changing unit for changing the set time of the timer when the provisional load exceeds the reference load as a result of comparison of the load comparison unit.