Laser Level Accuracy

[Dougryan]

Hi,
A few years ago I bought an inexpensive 360 degree laser level. I lost confidence in it quickly since getting the device level is key to accuracy. It had three bubble levels and it was adjusted with screw wheels. But if you're off by 1 degree, at 30 feet, you're off by 6 inches.

I started looking at auto-leveling laser levels. They have great accuracy, like 1/8" at 30 feet. That's awesome!
BUT, the self leveling function has a +/- 4 degree tolerance.
What does that mean? If the device is off by 4 degrees, at 30 feet your 'level' line is 2 feet off, but accurately within 1/8 of an inch.

Do these things really work?
That doesn't sound very accurate at all.
A string level or water level would make more sense.

Thoughts? Experience with self leveling lasers?
Thanks.

 

[4570Man]

Mine works great. I glued a disc level on the head so can set it some degree of level and the auto level function does the rest. A string level isn’t very accurate at all. A water level works but takes forever.

 

[GreyhawkUSA30340]

I suspect the tolerance of +/- 4 degrees means you have to manually get the head at least that level for the auto-level to work

 

[caver]

The guy that dug my basement likely had an error in his rotary laser as it sloped to the back by inches. The ponding water from rain doesn't lie. I would imagine some units need to be sent off for calibration. Mine has an error from the factory around 1/8" at 50' if my memory is correct.

 

[repete]

Mine shuts down if it is beyond the ability to self level.
I also check mine against a water level at about 75'. Set one end of the water level at the laser then go about 75' away and compare.
I have never tried going 90 degrees to the first check though. Perhaps I should but I would think it would be good all the way around if good one way.