steel corrosion resistant,heat treat to 48 rockwell-c,passivate per qq-p-35,external involute spline 0.7500 in. pitch dia,18 teeth,0.6960 in. minor dia,0.7833 in. major dia,by 0.310 in. thk,with 0.437 in. hole thru 0.030 in. excentric of pitch dia general characteristics item description