A method and apparatus (20) for ultrasonic bonding or other processing can include a rotatable ultrasonic horn member (28) and a rotatable axle member (34). The axle member is operatively joined to the horn member (28), and can provide a node plane (38). An isolation member (42) can be operatively joined to the axle member (34), and may have a location that is operatively proximate the node plane (38) of the axle member (34). In a particular aspect, the isolation member (42) can exhibit high rigidity. In a further feature, the isolation member (42) is capable of bending under a horn-life range of sonic frequencies to provide an operative component of motion along a radial direction (102), and an operative component of motion along an axial direction (100) of the isolation member.