Any thoughts on where to find "true level"?

[Hitch]

That's not the issue - it can happily measure a flat, and then measure a right angle at exactly 90 degrees. What I don't know is whether that flat is exactly level with, well, The Earth

You know the earth isn't flat though, right?

 

[Robotstar5]

You know the earth isn't flat though, right?

There was a member who would have argued that point

 

[skotl]

Link to the level please

Looking for the order in my emails and can't find it (yet) but I did find an Amazon order for a self-levelling laser, which should actually fix my original problem (assuming it's accurate, of course...)

 

[Screwdriver]

That's not the issue - it can happily measure a flat, and then measure a right angle at exactly 90 degrees. What I don't know is whether that flat is exactly level with, well, The Earth

The level is an angle finder, you can use it to MAKE any surface perfectly level, then use that new level to set the calibration. It only measures level in one linear direction on a plane, therefore when you turn it exactly 180 degrees (turn it exactly around) it will give you a “difference” measurement. Perform the above and keep recalibrating the level until the difference is zero.

The “trick” is that when you turn it 180 degrees it has to give you exactly double any error with respect to gravity. So if it is telling you “zero” when it’s resting on an angled plane, turn it 180 and it will display double the actual error angle.

I am struggling to think of any other way to explain this.

 

[brightspark]

There was a member who would have argued that point

WHO

 

[skotl]

The level is an angle finder, you can use it to MAKE any surface perfectly level, then use that new level to set the calibration. It only measures level in one linear direction on a plane, therefore when you turn it exactly 180 degrees (turn it exactly around) it will give you a “difference” measurement. Perform the above and keep recalibrating the level until the difference is zero.

Apologies, but we're missing each other. This meter (can't speak for any others) reads exactly zero when I flip it over.

To give an extreme example - if I put it on a 30 degree angle and (stupidly) went through the calibration sequence it would now be convinced that 30 was zero. If I turned it over and put it on that same 30 degree plane it would tell me that it was at zero again. If I then put it on whatever-passes-for-true-ground it would swear to me that it was at -30.

I think I'm going to go with my self-levelling laser and then compare that to the bath idea - keeps me out of the pub...!

 

[eLuSiVeMiTe]

The level is an angle finder, you can use it to MAKE any surface perfectly level, then use that new level to set the calibration. It only measures level in one linear direction on a plane, therefore when you turn it exactly 180 degrees (turn it exactly around) it will give you a “difference” measurement. Perform the above and keep recalibrating the level until the difference is zero.

This. Again.

Everytime a level comes out of the bag it gets tested flipped and tested again.
Level or not if the bubble is in the same place it's good to use.

 

[skotl]

It doesn't have a bubble, only a digital display

 

[eLuSiVeMiTe]

It doesn't have a bubble, only a digital display

Stick it on top of a spirit level then.
Get it as level as possible and hold calibrate again.

 

[Seadog]

To give an extreme example - if I put it on a 30 degree angle and (stupidly) went through the calibration sequence it would now be convinced that 30 was zero. If I turned it over and put it on that same 30 degree plane it would tell me that it was at zero again.

Don't flip it, turn it end for end.

 

[eLuSiVeMiTe]

Same difference but yours will be a digital reading.

 

[slim_boy_fat]

What I don't know is whether that flat is exactly level with, well, The Earth

You need a trip to Discworld then.....

 

[Farside]

All very well, but what if you venture off out and the gravity down the road isn't quite the same as at home?

 

[Brad93]

I think OP is missing the simplicity of checking a level (or many other types of precision instruments that read the opposite whe used inversely)

Give me 10 minutes I’ll do a video.

 

[Robotstar5]

You need a trip to Discworld then.....

Providing the Turtle's flying level....

 

[mr migwire]

i bet you say "Make the noise..."

 

[Brad93]

Actually, a video isn’t going to help you, because if you can’t understand from the above explanations or the Bosch article I linked to, then you’re not going to understand.

I could calibrate my level on the ****.

There is a difference between calibrate and zero.

I could put it 10mm high at one end, calibrate it, flip it so it’s 10mm high the other end, then put it on the table, which is level, and it would read 0.0°.

If you can’t get your head around it I can’t figure a way to explain it.

 

[Screwdriver]

Apologies, but we're missing each other. This meter (can't speak for any others) reads exactly zero when I flip it over.

To give an extreme example - if I put it on a 30 degree angle and (stupidly) went through the calibration sequence it would now be convinced that 30 was zero. If I turned it over and put it on that same 30 degree plane it would tell me that it was at zero again. If I then put it on whatever-passes-for-true-ground it would swear to me that it was at -30.

I think I'm going to go with my self-levelling laser and then compare that to the bath idea - keeps me out of the pub...!

I think we're getting somewhere! If you set it on a "known" 30 degree slope then accidentally hit calibrate, it will call that angle zero. Are you with me?

Now when you turn it through 180 degrees and put it back on the same slope, it will read 60 degrees (or 300 depending on your model of level). DO NOT TURN IT UPSIDE DOWN!

So let's pretend you can stuff a wedge under that 30 degree thing, you want to wedge it by half the error being displayed which in this case we happen to know is half of 60 i.e. the 30 degrees you want to remove to give yourself a calibrated level surface. In general though, even if you don't know what the error angle is when it is reading zero, just turn it 180 and wedge up the surface until you remove half the reading, then hit calibrate, then turn it again, and again, and again...

 

[Parm]

You know the earth isn't flat though, right?

Don’t you know?

He’s got a different level for that !

We shall be discussing how to calibrate that next week

 

[Barking Mat]

Whether the earth is flat or round, gravity will give flat on a spirit level.

Another beer, go on then.