How do you tell if a level is accurate?

[Ralph Mowery]

I just switch them one end to the other. If it is level (plumb when checking the vertical) in both directions, I assume it is correct.

[Trol Odioso]

the level could be straight as an arrow and still read wrong, dummy

sometimes i think youre half a bubble off

[RealPerson]

How do you tell if a level is accurate?

I have one that shows one thing, and if I reverse it's position (flip it over), it's different. I quit using that one, and bought a new one. But how do I know that the new one is accurate? Just like anything, *new* does not mean it's good. Many products are defective when purchased. There are ways to test electrical items, and machines. Most hand and household tools can be tested by just looking at them and making sure they are not flawed, but how does a person test a level?

I think I have a fairly good "eye" when it comes to something being level of not, and I could see that they did not appear level with that old one I had, but when I flipped it, it appeared level to the eye. How that thing could measure level in one direction and not in the other is still a mystery to me. After all, it's just a bubble in some liquid. All I can figure is that the vial with the bubble was not lined up properly in the tools body....

Either way, I got tired of fighting with it, and just replaced it. I was not worth the hassle for a $12 level.

But is there any way to test them? How are they tested when they are manufactured?

[RealPerson]

That' what I was doing with that old level, and what showed "level" in one direction was NOT level in th other direction. That's when I knew it was time to buy a new level.

[Mr Pounder Esquire]

They can leak. HTH

[Unquestionably Confused]

Think about this a moment as you ask how to test a level:

If you KNOW it's not working since reversing it in the same plane results in different results, why then would you think the new level is NOT working if you reverse it in the same plane and get the exact same results either way.

[clare]

If a level reads differently end for end it is not accurate. If it reads level both directions it IS accurate. There are no other possibilities.

[philo]

+1

[hrhofmann]

Float it in the middle of a uniform density piece of wood in a sink. That's about as close to level as you can do/find.

[Vic Smith]

I occasionally check against another level - or three. Don't you have more than one? I have 6-7 for different purposes. My favorite is one like this:

It's accurate enough for checking my other levels, but most of the time I just use this. It's good for sloping too, like with gutters.

[Micky]

That's how you know it's not accurate.

Same way. I would have checked it while in the store, before I bought it.

A $12 level is probably not adjustable, but some are. OTOH, this is not an adjustment that changes over time.

See your top line. Or they may have a known level surface, but I think the first method is better.

But you've only tested the horizonal glass of the level. Don't you have ones for vertical and 45^ too?

[Harry K]

Since you already knew the answer, why did you ask? You don't even need to check both level and vertical, if it is off in one, it is also off in the the other.

Harry K

[clare]

Not necessarily, as they are two different "levels" in one stick. Either one could be correctly installed. Either one could be incorrectly installed.

[Micky]

I don't think so. It could be off in one because the surface is not level. If it reads the same when reversed, the surface isn't. Only if it's also off in the other direction and by the same amount, to the extent one can tell, does one know the surface is level to the extent one can tell.

[Harry K]

Yep, the devil is in the details and I forgot that one little detail :)

[songbird]

i was going to say float it on a small puddle, but that would imply that the level itself is also manufactured in a balanced manner, which may not be the case, but the surface of a small puddle should be level...

another level that can be rigged up quickly if you have some clear tubing is to put some water in it and then hold the ends apart and upright and the water level of the two spots where the water are at should be level.

songbird

[FrozenNorth]

Check some surface you presume is level, then flip the level end for end and check the surface again. Any error should at least be equal in both directions.

[Harry K]

Water levels are a wonderful thing but there are things that can throw them off.

Check the line to be sure there are no bubbles in it. I don't know why that would throw it off but the books say it does.

Be sure the temp of the water is the same through the length. Can be done by running fresh water through it just before taking readings.

Do not have one portion in shade and one in sun.

[Sam E]

"A difference which makes no difference is no difference."

That is, if you can't tell don't worry about it.

[John G]

This is the EASY SIMPLE way without all the pipes puddles and other stupid suggestions. lol All the rest of this thread is a waste of bandwidth. :-?