These custom long socket head machine screws were manufactured domestically using 4140 alloy steel material with heat treatment to reach 37-44 Rc hardness.  Two sizes were produced together in this run: 8-32 X 5.43″ length with thread length of 5/8″ and 8-36 (an odd thread pitch requested for this one) X 6-3/8″ with the same 5/8″ thread length requirement.  The thread was cut rather than rolled for these parts and the hex drive was broached.