Know How: Ball Bearings
One of my favorite science fiction books when I was a kid was Jules Verne’s The Mysterious Island. It’s been a few decades, but I seem to recall a party of intrepid adventurers being stranded on a volcanic island, where they managed to reconstruct modern (1860) technology more or less from scratch. There are a few reasons why this wouldn’t work, starting with the fact that volcanic islands don’t have iron ore, but the problem is still interesting. The modern world is utterly dependent on thousands or millions of technological devices, so I thought I might start finding out how a few of them were made. One pretty important invention that we probably don’t think much about is the roller bearing, but it plays a critical role in all sorts of machinery. Marble players and others have long admired the shiny and seemingly perfect spherical roller bearing. So how do you make one? If you have played with wax or clay, you probably have a clue. If you roll that piece of wax between your pal...