Steel; 12.750 in. Od of flange portion; o.562 in. Flange thk; 8 holes 0.577 in. Diameter equally spaced on 11.500 in. Bolt circle dia; 4 holes 0.312 in. Diameter counterbored 0.625 in. Diameter 0.450 in. Deep; equally spaced on 6.750 in. Bolt circle dia; 5.375 in. Id; 2.547 in. O/a h