Checking Your Laser Level’s Calibration
Following is a guide on checking your laser level’s calibration. The Laser Level review have produced a number of guides on how to calibrate various models of laser level. However, we have never really covered how to check you laser for calibration in the first place. In the following guide we will look at how to check the horizontal calibration of your rotating or 360° 3D line laser. Vertical, plumb and square is a separate topic and will be covered in a future post.
Calibration checking methods
You could of coarse compare the levelling results of your laser to another laser level. But this can often cause more problems than it solves. The best way is to check your laser against its self, very much like checking a spirit level.
With a spirit level you place the level on a surface and look at the position of the bubble, lets say that the bubble is touching the left line and a 2mm gap to the right line. Now rotate the level 180° on the same surface in the same location and agin look at the bubble. If the bubble is again in the same position touching the new left line and 2mm from the new right then the spirit level is calibrated and working well. If the bubble is in a different position then the level is out, note that the surface does not need to be perfectly level for this method.
To check the calibration of a laser level you will need a room which is not too brightly lit. It will need a stable and reasonably level surface such as a table or tripod set up about 5 to 10m away from a wall.
A laser has two axis at 90° to each other, you need to check both axis to determine if the laser is within calibration. Many rotating lasers have an indication of the two axis on their casings often marked with an “X” and “Y”. On a laser which does not have these markings you will need to choose an “X” and “Y” axis.
Place the laser on the surface/tripod and aim the “X” axis at a wall, turn on the laser and make sure you can see the laser beam. Place a piece of paper on the wall and mark the height of the laser. Next rotate the body of the laser 180° and again mark the height of the laser on the paper. If the two marks you have made are are exactly the same height then the calibration of the “X” axis is good. Note that the further away from the wall the laser is the more accurate your calibration check is. Now we need to check the second axis “Y”. So, now face the “Y” axis to wall mark the height and rotate the body of the laser by 180° and mark the height again. As with the “X” axis the two heights should be the same.
All laser levels have a tolerance the the manufactures state in their specifications such as +/- 2mm at 20m. If in the example above the laser is 10m from the wall and the difference between the two marks for one of the axis is 2mm. Then level point would be half way between the two marks. So the laser is within +/- 1mm at 10m (+/- 2mm at 20m) and just within manufacturers tolerance in this instance.
Rather than producing lots of diagrams for this method I have found the following video by RedBack Lasers. This video showing this method being used.
This method of self checking calibration is a great way of finding out if your laser is at least working close to tolerance. It does not replace a professional check using specialised equipment such as what you would find at a specialist laser level service centre. Also this method does not take into account checking vertical, plumb or square calibration which some laser levels will require.
It is possible to use this method to calibrate too. However, you need to make the process as accurate as possible. Ideally with a very level surface, the maximum distance to the wall as possible and a fine pen on graph paper.
Hopefully you will find this information useful. If so please consider a donation to keep the Laser Level Review operational.