A sleeved ultrasonic transducer has a two-part head mass, including a threaded sleeve and an outer housing that are composed of different materials. The threaded sleeve is preferably a metal such as titanium that provides superior thread strength for mating with a compression bolt, while the outer housing is preferably aluminum or ceramic or other metal or non-metallic material that provides good thermal heat sink capacity and/or transmission of vibrational energy. The combination of the two components provides an improved ultrasonic transducer.