An ultrasonic instrument includes a shaft assembly and an end effector having an ultrasonic blade, a clamp arm, and a clamp pad. The clamp arm is pivotally coupled with the shaft assembly. The clamp pad is configured to removably couple with the clamp arm while the clamp arm is pivotally coupled to the shaft assembly. The clamp arm includes a mortise and a pair of support gussets. The clamp pad includes a tenon and a pair of resilient projections where the tenon engages the mortise of the clamp arm and the projections contact the support gussets of the clamp arm.