Ultrasonic Horn for Ultrasonic Drilling Machine https://www.bjultrasonic.com/shop/ultrasonic-horn/ Ultrasonic drilling machines a method of brittle destruction by collision of abrasives which are forced against a work by an ultrasonically vibrated tool assisted by an appropriate  clamping force. The tool vibration can be of amplitude approx. 40-80 microns with frequencies of 25 kHz, sufficient to perform effective machining. Abrasives may be carborundum, boron carbide or diamond powder depending upon each work. Rougher grits provide quicker chipping but it rougher finish, Abrasives are usually used in slurry (mixed with water).