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.

 

[EddieWalker]

I bought a Spectra 200 laser level on Ebay about 20 years ago that's been awesome. I haven't used it in a few years, but when laying out a pad, running my drain lines and even when digging my big pond, it was used almost daily. Technology has improved, and prices have come down, but for me, I still want a name brand tool for something like this. Since I couldn't afford what they cost brand new, I kept an eye on Ebay for one in my price range. It took a few months, but eventually, it happened.

 

[kneedeep]

I have my old contractor rotary laser from working days that still is accurate to 1% slope at 300’. Paid about $800 for it new, bet they are double that now vs 10 years ago.

 

[dodge man]

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

I suspect this is the correct answer. I’m a retired land surveyor and took thousands of shots with a level but they were optical. About the last 15 years before I retired we got a digital level, it shot a rod that looked like a giant bar code. All of these were “automatic” levels. You set them up and get them just close to level with a bullseye bubble and we’re good to go.

There is a test called a “two peg” you can test a level with including a rotary laser level. It’s hard for me to explain but you can Google it and it just takes about 15 minutes. I can’t tell you how many contractors levels I checked that were so out of whack they were useless.

Just about any level is limited to about 300 feet or a little less to be accurate. If you can live with a tenth of a foot accuracy you can go much further.

 

[RandyT]

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

I suspect the same. Mine needs to be witin +/- 5 degrees to self level and then can dual slope to 8 degrees. Mine is supposed to be accurate to 1/16" at 100'