Most Spirit Levels Are Not Accurate, Even The High Quality Ones.... This guide will help you find a good one. It's easy to do once you know how.
Unfortunately this is absolutely true and very easy to prove. Most levels you pick up in a store, even the so-called quality levels such as Stabila and Stanley etc, will have at least one bubble seriously out of alignment, some will have both vertical bubbles out of whack AND the horizontal one too for good measure, (no pun intended).
This can have mildly irritating, or disasterous consequences, depending on what you are planning to do with the level. If you are just putting up shelves, you will probably get away with a slightly out of true level. If you are tiling, or attempting to align kitchen cupboards accurately. the results will look appaling and you will be left telling yourself, or , worse still, your better half will do it for you, that you are the worst D.I.Yer in the world.
The reason is that the slight error in most levels will compound themselves as you continue along a run, so that a 1mm error in the length of the level, by the time you have extended the line by 5 level lengths will be 5mm. Do this when tiling and the finished job will look like you threw the tiles up whilst standing at the bathroom door.
You can avoid this problem by testing the level in the shop before you buy it.
To check the accuracy of the horizontal bubble:
- Pick a surface in the store which appears fairly level. Put the level on top of it and mark with a pencil onto the worktop or counter, exactly where each end of the level is situated. (This is done so that you can repeat the test, knowing you are testing in the exact same location).
- Now look at the bubble. If it is a bit off being absolutely accurate, lift the low end and place a penny, or 2 or 3 until the bubble is exactly in the middle.
- Now pick up the level and turn it around so that the left end of the level is now on the right.
- Place the level back between the pencil marks and resting once again on the coins, (if you needed any), The bubble should now once again, be exactly in the centre.
- If it isn't, it's not you..... It's the level. It has not been set up accurately by the manufacturer. Put it back on the shelf and select another one.
Usually I find when i'm choosing a new level, that fewer than 1 in 10 is accurate. You will too. Why not let the other poor souls get the dodgy ones. You take your time and select one which is perfect.
What length level should you choose:
For best results you should always use the longest level which will fit on the surface you are testing. If you can't afford to buy several levels, buy one 2 feet (600mm) long, which you have tested carefully and then pick a piece of very straight wood or other material which is closer to the length of the surface you are testing and place this on the surface you are trying to check with the level on top of it. By keeping your level tight against this longer length of wood, the new length becomes a longer level.
One last tip. Don't ever leave your level where it might fall over. Some levels can tolerate this kind of abuse, many can't. Also, it is good practise, before you start to tile a wall or fit kitchen cupboards, that you go through the testing process once again. The peace of mind you will have, knowing you can trust this most important of tools is worth every one of the few minutes it takes to carry out the test.
There is one slight downside. If you still make a muck up of the job, you now have no excuses left. Choose carefully and look after your level and it will serve you well for life.
p.s. You can test the vertical bubbles too, you just need a little ingenuity, or a spare pair of hands to hold the coins while you position the level. Remember, the pencil marks are there to ensure you are testing each time in exactly the same place.