Steel, carbon 12 l 14 specification qq-s-637, groove 0.2545 in. Min 0.2605 in. Max w, 3.490 in. Min 3.506 in. Max dia, 0.031 in. By 45 degrees both sides, center opening 1.000 in. Dia; chamfered 0.016 in. By 45 degrees max, other end 0.751 in. Approx dia, 1.030 in. Approx w, 3.866 in. Min 3.870 in. Max od