Most screw heads are formed in a cold header. If you've never seen one running, you'd think it was magic. Wire goes in one side, and using a surprisingly simpl

Most screw heads are formed in a cold header. If you've never seen one running, you'd think it was magic. Wire goes in one side, and using a surprisingly simple and old (WWII era) machine made with some heavy castings, plain bearings, oily camshafts, and the magic of tool steel, the wire is incrementally upset, extruded, formed, punched, and thread rolled. Screws roll out the other side at an astonishing rate - hundreds per minute. I can't share video of my customer's machine running, but here's one from Youtube: https://youtu.be/WoN2KKfbzLA?si=iN42q6n1wBkoJ-gS&t=187 https://youtu.be/WoN2KKfbzLA?si=iN42q6n1wBkoJ-gS&t=187 I imagine that many screws on spacecraft use CNC-cut machine screw threads, and have significant QC measures in place, but I'd be unsurprised if they had cold-formed Torx or hex heads.