A textile jet subassembly includes a textile jet or jet nozzle mounted on a base support. An upper impact plate and a lower insert plate form the yarn channel passing through the jet or jet nozzle. A jet interface and a threading slot communicate with the yarn channel and the sidewalls above and below the threading slot are coplanar to form a smooth surface. Multiple alignment or registration recesses and cooperating pin fasteners are spaced from the yarn channel on the same side of the yarn channel to properly align the side walls above and below the threading slot.