Plumb Bob

A plumb bob is a pointed weight attached to the end of the string, and is used to find a vertical reference line called plumb. Plumb is the vertical equivalent to a spirit level. Plumb bob have been around for thousands of years, dating back to Ancient Egypt. The tool is also used in surveying, allowing the user to find nadir (the local vertical direction pointing towards gravity), and in tools such as steel tape and theodolites.

Plumb Level from Johnson LevelAs an interesting side note, the English word ‘aplomb’ is derived from the French aplomb denoting the concept of standing upright.

How to Use A Plumb Bob

  1. Measure two to three few inches away from the top of the wall, and make a mark.
  2. Set a nail in the mark.
  3. Hang the plumb bob on the nail, letting gravity draw a vertical reference line for you.
  4. When the plumb bob is done oscillating, measure the distance from the wall. If it matches the measurement at the top of the wall, your wall is plumb.

Check out the entire line of plumb bobs from Johnson Level.

For more how-to information, have a look at our guide of how-to’s.