An apparatus comprising: (a) a shaft assembly comprising: (i) a first tube, (ii) a second tube coaxially disposed within the first tube, wherein one of the first tube or the second tube is configured to translate relative to the other of the first tube or the second tube, and (iii) a distally projecting tongue (354, 372) fixed to either the first tube or the second tube, wherein the distally projecting tongue comprises pin holes; and (b) an end effector comprising: (i) an ultrasonic blade extending from the shaft assembly, and (ii) a clamp arm pivotally coupled to the distally projecting tongue (354, 372) of the shaft assembly, wherein the clamp arm is configured to pivot toward and away from the ultrasonic blade in response to relative translation between the first and second tubes, wherein the distally projecting tongue (354, 372) is configured to flex relative to the first tube and the second tube in response to the clamp arm grasping tissue, wherein the clamp arm further comprises a first pair of integral pins, characterised in that the clamp arm further comprises a second pair of integral pins; and that whichever of the first tube and second tube to which the distally projecting tongue is not fixed comprises a pair of vertically elongated slots configured to couple with the clamp arm, and wherein the first pair of integral pins are configured to pivotally couple the clamp arm with the pivot holes of the distally projecting tongue, and the second pair of integral pins are configured to pivot and translate within the pair of vertically elongated slots, wherein the second pair of integral pins are configured to translate within the pair of vertically elongated slots in response to the distally projecting tongue (354, 372) flexing relative to the first tube and the second tube (a) a shaft assembly comprising: (i) a first tube, (ii) a second tube coaxially disposed within the first tube, wherein one of the first tube or the second tube is configured to translate relative to the other of the first tube or the second tube, and (iii) a distally projecting tongue (354, 372) fixed to either the first tube or the second tube, wherein the distally projecting tongue comprises pin holes; and (i) a first tube, (ii) a second tube coaxially disposed within the first tube, wherein one of the first tube or the second tube is configured to translate relative to the other of the first tube or the second tube, and (iii) a distally projecting tongue (354, 372) fixed to either the first tube or the second tube, wherein the distally projecting tongue comprises pin holes; and (b) an end effector comprising: (i) an ultrasonic blade extending from the shaft assembly, and (ii) a clamp arm pivotally coupled to the distally projecting tongue (354, 372) of the shaft assembly, wherein the clamp arm is configured to pivot toward and away from the ultrasonic blade in response to relative translation between the first and second tubes, wherein the distally projecting tongue (354, 372) is configured to flex relative to the first tube and the second tube in response to the clamp arm grasping tissue, wherein the clamp arm further comprises a first pair of integral pins, characterised in that the clamp arm further comprises a second pair of integral pins; and that whichever of the first tube and second tube to which the distally projecting tongue is not fixed comprises a pair of vertically elongated slots configured to couple with the clamp arm, and wherein the first pair of integral pins are configured to pivotally couple the clamp arm with the pivot holes of the distally projecting tongue, and the second pair of integral pins are configured to pivot and translate within the pair of vertically elongated slots, wherein the second pair of integral pins are configured to translate within the pair of vertically elongated slots in response to the distally projecting tongue (354, 372) flexing relative to the first tube and the second tube (i) an ultrasonic blade extending from the shaft assembly, and (ii) a clamp arm pivotally coupled to the distally projecting tongue (354, 372) of the shaft assembly, wherein the clamp arm is configured to pivot toward and away from the ultrasonic blade in response to relative translation between the first and second tubes, wherein the distally projecting tongue (354, 372) is configured to flex relative to the first tube and the second tube in response to the clamp arm grasping tissue, wherein the clamp arm further comprises a first pair of integral pins, the clamp arm further comprises a second pair of integral pins; and that whichever of the first tube and second tube to which the distally projecting tongue is not fixed comprises a pair of vertically elongated slots configured to couple with the clamp arm, and wherein the first pair of integral pins are configured to pivotally couple the clamp arm with the pivot holes of the distally projecting tongue, and the second pair of integral pins are configured to pivot and translate within the pair of vertically elongated slots, wherein the second pair of integral pins are configured to translate within the pair of vertically elongated slots in response to the distally projecting tongue (354, 372) flexing relative to the first tube and the second tube