A mounting assembly for a spot-joining apparatus comprises a first support arm (24). The first support arm (24) has a mounting surface (26), and receiving portion configured to receive an actuator or an anvil. The mounting assembly also comprises an alignment bracket (28) configured to engage with the actuator or anvil. The alignment bracket (28) is movable between a plurality of locations on the mounting surface (26) of the first support arm (24). The mounting assembly further comprises a clamp assembly (52, 29, 66a, 66b, 70, 70b or 52, 29, 88, 92, 98, 90, 96) configured to secure the alignment bracket (28) in any of the plurality of locations.