1. Circular Saw
In the late 18th century, a religious sect known as the Shakers emerged. Shakers valued living communally (albeit celibately), equality between the sexes and hard work. Tabitha Babbitt lived in a Shaker community in Massachusetts and worked as a weaver, but in 1810, she came up with a way to lighten the load of her brethren. She observed men cutting wood with a pit saw, which is a two-handled saw that requires two men to pull it back and forth. Though the saw is pulled both ways, it only cuts wood when it's pulled forward; the return stroke is useless. To Babbitt, that was wasted energy, so she created a prototype of the circular saw that would go on to be used in saw mills. She attached a circular blade to her spinning wheel so that every movement of the saw produced results. Because of Shaker precepts, Babbitt didn't apply for a patent for the circular saw she created.