Saturday, June 23, 2007

Which came first, the screw or the screwdriver?

The screw, surely? No - it was the other way round. Screws as we know them didn't catch on until about 150 years ago. That was when a method of making them cheaply by machine was invented. Until then the few wood screws that were in use did not have points. However, carpenters had been knocking nails into wood for hundreds of years. As long ago as the sixteenth century it was discovered that giving a nail a twist helped tighten it. In the same way, cutting a slot in the head of the nail so that it could be twisted in the other direction was the only way of getting a nail out. In both cases a tool with a short, blunt blade was used. It looked a bit crude, but it was a screwdriver all the same.