Steel carbon 46540 class 5, 0.562 in. Od 0.438 in. Lg small od, 1.562 in. Od 0.437 in. Lg largest od, 2 holes no. 31 drilled through on 1.250 in. Bolt circle, 1.035 in. Min 1.040 in. Max diameter recess 0.250 in. Min 0.255 in. Max lg, 0.875 in. O-a lg, rockwell c45-50