A full width read and/or write assemblies, such as a full width thermal ink jet printbar, is disclosed, having materials with both a high thermal coefficient of expansion and a low thermal coefficient of expansion. A suitable adhesive which provides lateral give while firmly holding the respective components together provides dimensional stability to the printbar element having a low thermal coefficient of expansion when components having high thermal coefficient of expansion are assembled thereto. The flexible or floating mounting enabled by lateral give of the adhesive allows for the application of cost effective materials with a high thermal coefficient of expansion to be used for support functions such as, for example, circuit boards and ink manifolds. The flexible or floating mounting relieves shear stress cased by a differential in the expansion or contraction of materials having a different thermal coefficient of expansion. Since the thermal expansion of the various components expand and contract from a center location thereof, this center location is bonded by an adhesive which does not provide lateral give, so that alignment between parts are maintained while the remainder of the respective components float relative to each other and prevent thermally induced stresses which tend to cause warpage.