A component (34A, 34B, 34C) has a core formed of a stack (25, 36) of sheets (20) of material with cutouts (22A) aligned to form passages (38) in the core. An outer casing (29) spans the stack axially (51), brackets at least parts of opposed ends of the stack, and holds the sheets together in axial compression (46). Respective cooperating elements (30, 31) on the casing and the stack may register the casing with respect to the stack. Pins (24) in some sheets may engage holes (23) in adjacent sheets to register the sheets with each other. The casing may be segmented (28A, 28B, 28C). A hoop (66) may be compressed around the segmented casing. A gas turbine fuel injector may be formed of a stack (36) with an inlet element (44) compressed (46) onto the stack by the casing (29).