A plumb bob is a carpentry tool used to show if something is straight (or “plumb”). By hanging vertically, plumb bobs use gravity to determine straightness. Here’s how to use a plumb bob: Secure one end of the string above the area you want to check. Allow the heavy plumb to hang and settle so you can make your mark as demonstrated in this video. Plumb bobs are easy to use for projects in your home! Did you know? Plumb bobs have been around for thousands of years, dating back to ancient Egypt. D