I saw a show on a local cable channel last night about the development of radio circuit, proximity detonated, anti-aircraft shells, before and during World War II. Every now and then we get a really cool show on one of the college/public access channels. Anyway, the engineers who designed the circuits could produce them with about 30% reliability. Reliability meaning that they work when you shoot them. They had a group of "young women" who, according to the engineer being interviewed, called themselves the "wench bench". The "wench bench" could produce fuses with more than 60% reliability. Remember, these are tube (valve) circuits being installed in artillary shells (0 to Mach 2 in 0.25 seconds?).