The first wire wrapped equipment I ever saw was in the early '70s at the plant in Phoenix where Honeywell made big mainframe computers.

Most of the electronics in those computers was in 14- and 16-pin DIP packages mounted on wire wrap boards that they manufactured in the Phoenix plant.

They started by punching long rows of holes in raw fiberglass/epoxy board material similar to the stuff that printed circuit boards are made of today. Then they stuffed the holes with wire wrap pins. The holes were sized such that the pins would stay in place by friciton alone.

The pins in each row were 0.1" apart, to match the spacing of the IC legs. The rows themselves were just a tad wider than 0.3", so that if you stuck an IC between two rows of pins, the springiness of its legs against the pins would hold it in place. After loading a board with ICs in this way, they wave-soldered the IC legs to the pins to make a permanent assembly. If I recall correctly, there were something like 50-100 ICs on each board.


Then they used some gigantic automatic machines to wire wrap the connections on the opposite side of the board.

The net result was a reliable, easy-to-repair board with very low raw materials cost. (There were no fancy sockets or anything, just the raw board material and millions and millions of little pins.) And of course they were building enough boards to amortize the cost of the very elaborate manufacturing equipment involved.

-- Russ