Anyone who works with stainless-steel screws eventually finds out that, yes, they do rust. Corrosion may occur after a single season on boats that sail the salty seas, or after several years on window and door frames. The solution sounds like it should be obvious: Switch to stainless-steel tools, which generate stainless particles that resist corrosion. The problem is that stainless, by itself, is too soft for high-volume factory work. Wera Tools spent two years attacking the problem. Its solution includes a final cryogenic tempering step that supercools its stainless-steel tools in a vacuum chamber.