I just bought a new 60 cm bubble level from a relatively reputable brand - Empire - and I had to go through six of them in the store before I found one that was accurate. I own three longer ones, two of which have been miscalibrated since the day I got them. The third one would have been as well, but luckily I checked it before buying.
It would be so easy to just add a small adjustment screw for calibration. I don’t understand why they don’t do that. Even the more expensive ones I’ve seen don’t have one. I’ve developed serious trust issues because of this.
Also, in case you didn’t know, you can check the accuracy by rotating the level 180 degrees and seeing whether the bubble stays in the same place.
This might be a stupid question, but what do you calibrate against?
I can’t with certainty say that anything in my home is level.
You don’t need a level surface for it. Say your level is off by 5 degrees. On a 5 degree incline it’ll either show 0 degrees or 10 degrees depending on which way you have it. Just adjust it untill you get the same reading both ways. This is easier to do on a digital level but the same principle applies on a bubble level as well - you just need to eyeball it.
I swear to god there’s a meme of Hank Hill checking his levels with other levels that I desperately want to post here.
(bluegrass ep. Four and a half mins in)
Not mixing it up with the WD40 one?
I think I know what you’re talking about, but it was from the TV series Monk. See my other comment in this thread.
Nope, there was a koth one. Hank shoulda known better than to trust a yard sale level.
Huh, gonna have to look that up, add it to my collection of obscure references. =)
6.09 - The Bluegrass is Always Greener. Four and half minutes in
Thanks!
You need a level checking level.
In all seriousness, they make levels like this, they’re just a more high-dollar, specialty item. At work we have a “true table”, a tested flat and level metal surface, to check and adjust them.
Edit: Here are some examples
Doesn’t have to be level, just flat. Ox tools example
Our process isn’t anywhere near that elaborate. We’re just making a quick check to see if a level has been knocked out of whack somehow. But we’re not a machine shop either, we use the levels for verifying weight and balance on small aircraft.
Question: if the bubble is correct on one side, but incorrect on the opposite side, wouldn’t that suggest that one side is misplaned and any attempt at adjusting the bubble part would still come out inaccurate?
I guess maybe I’m not fully understanding the situation?
Artisan ‘wedge-level’
If you have a miscalibrated bubble level on a truly level surface, the bubble will sit more toward one side - say, left. Flip it 180 degrees, and it’ll shift to the right.
On an inclined surface, the level might read level one way and show incline the other way.
Here you could just adjust the screw until the bubble stays in the exact same spot no matter which way you flip the level.
That assumes that it’s the bubble tube that’s not installed evenly but doesn’t remove the problem the other person suggested, which is a non-flat or non-squared other side?
Not entirely. Like the OP mentioned, (may not have explained it well enough) you would just adjust the ampule’s rotation so that it will report the same offset either direction the level is oriented. I.E. if the bubble is 5mm to one side of the ampule when the level is facing one direction, it should report the same offset but at the opposite end of the ampule when the level is reversed.
I see what you’re saying. Make the bubble offset “evenly”, but then you’re doing Kentucky windage with your bubble everytime?
I think this becomes entirely moot if you mark which side of your level is the “accurate” side. I have a torpedo level that’s damaged on one side, but I like that it has magnets, so I explicitly use the magnet side which I know is accurate.
does that make a practical difference?
Not at all, but neither does OPs request hahahah. There are more hard core leveling devices if a cheap bubble level isn’t good enough.
Okay, now I’m picking up what you’re putting down. Thank you! Off I go to test my levels! 😅
Here’s one extreme example of what they are describing, other situations might also be bowed, twisted etc.
Doesn’t matter. Most levels aren’t “two sided” like that anyway but have a top and bottom.
Well … Where to calibrate it then? You’d need a reference. Just a clear tube with water works all the time. But yes, it has some inpractical issues
You can use the same method you already used to check accuracy in the first place. It doesn’t even need a level surface - just make sure the bubble sits exactly the same distance from the lines when you flip the level the other way around.
Huh. I need to check mine now.
Machinist’s levels usually have adjustment screws on each end: https://www.ebay.com/itm/406571322248
Here’s one in use: https://www.youtube.com/watch?v=ue5W2fwKb4s
I fully agree with you. I’ve got a very old wooden one which has adjustment screws, and I’m pretty sure older “Stabila” brand ones used to be re-calibratable - though it doesn’t look like any of their newer ones are. I don’t remember seeing adjustment screws on any other levels though. I suppose at least they’re “guaranteed level” for 10 years, and they can take quite a beating and still work properly.
