Abstract: A nozzle for use in water jet cutting includes distinct upper and lower bodies held together by a locking device. The upper and lower bodies each include a mating surface, the two mating surfaces being of complementary shape and held in close contact by the locking device. The upper body includes a fluid inlet and a plurality of fluid outlets. The lower body includes a mixing chamber and the fluid outlets are in fluid communication with the mixing chamber. A jewel having a stream-forming aperture formed therethrough is mounted in each of the fluid outlets and arranged so that the centerlines of the stream-forming apertures converge to a focal point within the mixing chamber. The nozzle includes a nozzle exit passage having a first end in fluid communication with the mixing chamber, the focal point of the centerlines being adjacent the first end of the nozzle exit passage. The upper body includes an abrasive inlet connected to an abrasive passage that opens into the mixing chamber.