An ultrasonic instrument comprises an ultrasonic transducer, an acoustic waveguide, and an ultrasonic blade. The acoustic waveguide comprises a bore extending through the waveguide, an anchor pin, and an acoustic isolator. The anchor pin is insertable through the bore and is operable to longitudinally anchor the acoustic waveguide relative to the ultrasonic instrument. The acoustic isolator is radially disposed about the acoustic waveguide and is operable to acoustically isolate the acoustic waveguide from the ultrasonic instrument. The acoustic isolator comprises an opening extending through the isolator. The opening is configured to receive the anchor pin. The ultrasonic blade is in acoustic communication with the acoustic waveguide such that the ultrasonic transducer is operable to drive the ultrasonic blade to vibrate ultrasonically via the acoustic waveguide.
