"MATL STEEL MIL-S-5626 COMP 4140 COND D,DIFFUSED NICKEL-CADMIUM PLATED,FIRST END 1.231 IN. LG WITH 1/4-28 UNF-3A THD 1.000 IN. LG,SECOND END 2.600 IN. LG WITH 1/4-28 UNF-3A THD 1.000 IN. LG AND 3/8-24 UNF-3A THD 1.264 IN. LG,ONE 9/16 IN. W ACROSS FLATS HEX 0.219 IN. THK,ONE GROOVE 0.034 IN. DEEP BY 0.096 IN. MIN TO 0.106 IN. MAX W,HEAT TREAT 150000 T0 180000PSI,MACHINED SURFACE ROUGHNESS 125 OR BETTER"