How To Calibrate Your Spirit Level


Spirit levels are one of the most valuable tools for people working on woodworking and construction projects. They are simple devices consisting of a sealed glass tube partially filled with alcohol or another liquid and an air bubble to indicate how parallel or perpendicular a surface is. While most people might be aware of the functions of the spirit level, only a few know that the spirit levels should be calibrated and checked for accuracy. Read on to learn how to calibrate the spirit levels for accuracy. 

Why should you calibrate a spirit level?

The simple answer to this question is if uncalibrated, the spirit levels can be wrong. Of course, they are generally highly accurate right out of the box as they’re usually calibrated before being shipped. However, as with several other measuring tools, spirit levels can be less accurate over time, which means they need calibration.

How to check the accuracy of your spirit level?

The next question is how you can tell if your spirit level is accurate or inaccurate. Well, you can do so through an easy step-by-step process. It applies to vertical and horizontal levelling because a good spirit level can be used on walls and floors. The only difference is the accuracy of the vertical plumb. You should hold it vertically against a wall, and for horizontal accuracy, you must lay it on a flat horizontal surface.

So, here are the steps to check the accuracy:

You must refer to the owner’s manual for calibration if you have a digital spirit level. Even a digital spirit level should be relatively easy to calibrate.

Find a level/flat surface – you need to find a surface that is 100% level before you start the calibration process. If the surface isn’t level, you cannot accurately calibrate your spirit level, and hence you must use a surface that is already levelled.

Place the spirit level: After successfully identifying a flat surface, you should place the spirit level on that surface. Once you do that, take note of the exact position where the bubble rests. It should ideally rest precisely at the centre of the vial. If not, the spirit level is likely to be inaccurate. Remember that calibrating a bubble level on an uneven surface will give incorrect results.

Adjust the screws – on your spirit level, you’ll see a screw at each end of the vial. These are calibration screws to help you calibrate the spirit level. So, if your surface level is 100% accurate, but the bubble in the vial is not resting at the centre, you can adjust the screw until the bubble perfectly aligns. You must adjust the screws until the bubble is placed at the centre, between the vial’s two lines. Your spirit level is calibrated when the bubble rests in the middle of the lines.

You can also calibrate it as under:

  • Hold the spirit level against a flat wall or place it on a flat surface, as the case may be
  • Note the exact spot of its placement along the wall, floor, or surface of the vial of the level.
  • Check the vial to note the position of the bubble.
  • Once the position is duly noted, turn the level 180 degrees
  • If the spirit level is accurate, the bubble will be back in the same position within the vial even after you turn it.
  • Your spirit level is inaccurate if the bubble is not in the exact position within the vial for both directions.

Check out our vast collection of measuring tools if you are looking for high-quality spirit levels at affordable prices

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