Carpenters and homeowners alike can appreciate the benefits of keeping everything level and plumb. Paintings look better, desk drawers work better, and appliances run better if they are level and plumb. A bubble level, also called a spirit level, can help you accomplish these tasks. According to experts at level company Level Developments, “the principal of operation is that the bubble will move to the highest point of the radius as gravity acts on the liquid inside the vial.” Read a bubble level by setting it up, looking at the bubble and determining the results.
Measure for Level - Set the bubble level on top of the item that you plan to level to a horizontal plane. Put it down with the long side going across. Leave the level in place until you have finished with it.
Look at the position of the bubble in the vial of fluid that is in a cutout in the spirit level. Look at the vial that is on top when the level is in place, as there may be several vials on the level.
Check the vial for lines that are the same distance apart and one space where there are two lines farther apart in the middle. Notice the position where the bubble falls within the vial. If the bubble is not centered between the two middle marks on the vial, the object is not level.
Determine the problem if the object is not level. Correct the level by adjusting the height of one side of the object. Raise the left side or lower the right side if the spirit bubble lies to the left side of the center of the vial. Raise the right side or lower the left side of the object if the bubble lies to the right of center. When the bubble is centered, the object is level.
Measure for Plumb - Hold the level up to the side of the object you are checking for true vertical correctness, or plumb. Keep the level in this position until you have finished with it.
Check the position of the bubble in the vial on the top. This will be the vial on the short end.
Look at the position of the bubble within the vial. The object is out of plumb if the bubble is not centered.
Determine the problem if the object is not plumb. Move the top of the object to the right or the bottom to the left if the bubble lies to the left of the center of the vial. Move the top to the left or the bottom to the right if the bubble is setting to the left of center. When this bubble is centered, the object is plumb.