MALE SCREW HEAD PART WASHING METHOD

PROBLEM TO BE SOLVED: To enable effectively performing washing of particularly a screw grooved part of a screw on which a self-locking agent has been solidified by giving ultrasonic vibration to the washing liquid at the time of immerging the head of a male screw in washing liquid to wash the head part only and immersing it in the washing liquid while giving slight vibration to the male screw. SOLUTION: When the head of a male screw of a tightening member on which a self-locking agent has been applied in order to improve tightening force on tightening is immersed in a washing agent to wash the head part, ultrasonic vibration is given to the washing liquid and slight vibration is given to the male screw. As a means for giving the ultrasonic vibration to the washing liquid, for example, an ultrasonic vibrator transducer is arranged in the bottom part of a washing tank. As the method of immersing the head part of the screw or the like in the washing liquid, that in which in a state that the head part of the screw or the like is held by a holding jig, the holding jig is moved downward to immerse the head part in the washing liquid, or the like is given. As a method of giving the slight vibration to the male screw, that in which the slight vibration is given to the holding jig to indirectly give the slight vibration to the screw or the like, is given.