at an included angle of about one degree and the working length 18 39 includes two continuous helical flutes 21 22 formed in the peripheral surface the flutes have an arcuate curvature as best seen in fig5 and they have a pitch so as to define helical lands 24 on the outer periphery of the instrument an instrument of this general construction is further described in u s pat no 4 871 312 to heath and pending application ser no 07 679 628 filed apr 3 1991 fig6 and 7 schematically illustrate a machining apparatus for practicing the method of the present invention as will be further described below the method involves a unique machining process which has been found to efficiently produce endodontic instruments of the type described from a rod 30 composed of titanium alloy such alloys typically have a titanium content of at least about 40 percent nickel titanium alloys are preferred which typically consist of about 40 percent titanium and about 50 percent nickel in one preferred specific embodiment the alloy consists of 44 percent titanium and 56 percent nickel and no appreciable amount of other ingredients which could adversely effect the purity required for endodontic instruments the rod 30 from which the instrument is to be fabricated is conventionally supplied from the producer in a selected diameter which closely conforms to the diameter of the instrument being produced in this regard endodontic instruments are sized in accordance with established standards which range from a diameter at the pilot end 16 of 1 4 mm 0 062 inches size 140 to a diameter at the pilot end 16 of 0 06 mm 0 0024 inches size 06 in accordance with the illustrated embodiment of the present invention the.