"STEEL 8630,MIL-S-6050,150-170,000 PSI HEAT TREATED,HEAD DIM.,0.750 IN. HEX,0.250 IN. THK,0.212 IN. MIN,0.218 IN. MAX DIA CENTERBORE W/100.0 DEG COUNTERSINK 0.280 IN. W,1/4-28 UNF-3B THD 0.310 IN. LG,SHANK DIM.,0.500 IN. LG,0.363 IN. DIA,0.251 IN. MIN,0.258 IN. MAX DIA THROUGH CENTERBORE 0.440 IN. LG"