"STEEL ALLOY MIL-S-7420 CONDITION E,2.365 TO 2.370 IN. O/A DIA,0.135 TO 0.140 IN. O/A THK,CENTER HOLE 0.994 TO 1.002 IN. DIA,9 HOLES0.512 TO 0.516 IN. DIA ON 1.742 IN. CENTER DIA,9 HOLE OD SURFACE 16MICROINCH FINISH,RH AND LH FACE 8 MICROINCH SURFACE FINISH,ID AND ODSURFACE 125 MICROINCH FINISH,HEAT TREAT ROCKWELL C58 TO C62"