Abstract: An apparatus for holding a heat exchanger core 22 during a manufacturing process is disclosed. The core includes a first 24 and second 26 side support member disposed on opposite sides of an assembly of a plurality of interleaved tubes 28 and fins 30. The apparatus comprises a pair of elongated rod members 38, 40, releasably engaging locating apertures 34, 36, 34', 36' of the first 24 and second 26 side support members in an overlapping, crosswise relationship. The rod members 38, 40 apply constant compressive force between the side support members to hold the plurality of tube and fins together during the manufacturing process and prevent the heat exchanger core from skewing.