"STEEL,MIL-S-6758,4130,CONDITION D4,TUBULAR SHAPE WITH FLATTENEDAREA ON ONE SIDE,0.550 IN. MIN,0.553 IN. MAX LG,0.622 IN. MIN,0.628 IN.MAX OD,0.251 IN. MIN,0.253 IN. MAX DIA OF SQUARE HOLE THROUGH LENGTH,SETSCREW IN. FLATTENED SIDE,TAPPED HOLE 0.380 IN. DEEP,THREAD 6-32,NC-3B,FLANGED"