FIELD: machine tool manufacture, namely machine tools for ultrasonic treatment of outer and inner threads on end portions of tube blanks, tubes and their couplings, mainly in pump-compressor installations of oil wells. SUBSTANCE: machine tool includes frame, unit for clamping and rotating blank and unit for mounting changeable tool. In order to correct in automatic mode worn portions and errors of outer and inner threads in rather large range of their diameters, unit for mounting changeable tool is in the form of carriage moving in lengthwise direction. In housing of said carriage are mounted: ultrasonic head with vibrator, mechanism for suspending ultrasonic head and mechanism for fixing it in axial position. Changeable tool is forced to vibrator of ultrasonic head by means of sleeve that is spring-loaded in axial direction and it has flange engaging with flange of changeable tool. In order to lower dissipation of energy of ultrasonic oscillations, suspension mechanism of ultrasonic head may include at least two flexible members. One end of each flexible member is secured to ultrasonic head; its other end is spring-loaded relative to housing of carriage. EFFECT: enhanced efficiency of treatment. 6 cl, 6 dwg
