Some screws are turned by hand, others lost their head, and one looks like a sea monster. It might be time you read up on ...

If you're working with hex fasteners, whether that's furniture assembly or bicycle repair, you're going to need an Allen wrench.

In 1910, William G. Allen, owner of Allen Screw Manufacturing Company, began marketing hex wrenches, which had already existed in some form or another since the 19th century.