Abstract: This technique for assembling a print head for an LED printer has LED dice first assembled into precisely known locations on mounting tiles. A portion of the front face of each tile is left exposed beyond anything mounted on the tile. The tiles are then assembled with these exposed areas on a planar reference on an assembly fixture. Reference surfaces built into the fixture align the edges of the tiles, and hence the LED dice. Finally a mother plate is adhesively bonded onto the backs of the tiles. The adhesive accommodates thickness variations in the mounting tiles, and lack of flatness in the back surfaces of the tiles and the front face of the mother plate. Reference tiles copolanar with the reference plane formed by the front faces of the mounting tiles provide a z axis reference.