How to test accuracy of a laser level

Can anyone suggest a way to check the accuracy of a laser level? The one I have has a small tripod. I've been trying to think of an easy way to test it for accuracy. I thought about sitting it on a piece of wood floating in a very calm indoor swimming pool at night when the lights are off, and shining the laser onto the opposite wall of the pool - but that's not really an option as I don't have any friendly neighbourhood swimming pool owners nearby. There has got to be an easier way, isn't there?

TIA PhilK

Reply to
Phil K
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Use water to find your reference levels, but inside a clear flexible tube rather than a swimming pool ...

Reply to
Andy Burns

Yes. Trace it around a room until you get back to the start. If you hit your start point, it is fine.

Reply to
Tim Watts

Surely that only checks the repeatability of the rotation mechanism not the level itself?

Reply to
Bob Minchin

Reply to
alan_m

If its the type that looks like a level and has a laser on the end, then turn it on and hold it against a flat wall, level it with an additional external level, then mark the laser spot where it hits the end of the wall. Now invert the laser level and level it again using the external level. Check the laser spot hits the same mark.

If its the auto levelling type, then just project lines along a wall, and check them with a standalone level. Remember to reverse the standalone level to see that that is accurate.

Reply to
John Rumm

Wot a load of time wasting crap the wiki thing is just get a length of tube,stick one end under tap and fill till it comes out the other end

Reply to
F Murtz

Perhaps I was too brief. I am also assuming this is a static line not a rotating type.

Sit it on a table. Point at one wall. Mark on the left and the right ends of the wall where the line is (use masking tape or a postit).

Turn laser 90 degrees clockwise and fix so it lines up with the rightmost of the two marks on the last wall (now on the left end of the beam).

Mark the right end of the wall.

Repeat until you are on the 4th wall.

If the right and of the beam hits your 1st left end mark, you are golden.

If the laser has any slope in the beam, you will have progressively have gone upwards or downwards and will miss the mark. How much you miss the mark will tell you how far out the laser is.

It's a standard reckoning method...

Reply to
Tim Watts

Or just use the trace around method I described - no need for tubes...

Reply to
Tim Watts

In other words, get a good bubble level! Brian

Reply to
Brian Gaff

For the laser beam coming from the same end of the level yes. But it appears from other comments that some have a beam from both ends, now if that is an optically split beam a 180 degree rotation ought to show how well the beam agrees with the bubble, assuming the optics used for the split are good. If it's two lasers how you check that they aren't in an equal V (or inverted V) alignment I'm not sure.

180 degree rotation between two walls but with the distance from one wall much greater than the other, say 18" and 180".
Reply to
Dave Liquorice

But isn't the laser now pointing the other way?

I think I'm missing something with the word "invert" is that a rotation along the long axis that also assumes the level has faces on both edges and that they are parallel or is it and end to end rotation using the same face as the reference level?

Reply to
Dave Liquorice

No - you just turn the laser through 4 rightangles, markeing the wall on each turn until you get back to the start.

I am assuming a regular DIY laser that emits a long horizontal self levelling line like this:

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Reply to
Tim Watts

Tim Watts wrote in news: snipped-for-privacy@squidward.dionic.net:

This the exact model:

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(Got it at Lidl's several years ago, thinking I would surely need it some day. That day has now arrived...)

Thanks for the helpful suggestions.

PhilK

Reply to
Phil K

That's the type I've got, I just projected the line on the wall and checked it with a spirit level, though your method is fine.

However it the bit above John seems to be talking about the ones that look like a level and have a laser in the end, like this:

Though I to am confused as to exactly what he means.

Reply to
Chris French

Ah, I'm assuming something like this:

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Bit of a faff to set up but great for getting vertical guidelines for onto a wall for papering that has a 2" buldge in it. Or for a non-spiral guideline for a mid wall border with one edge that runs along a (non level) window cill.

Self levelling may have it's uses but in the real world nothing is plumb or square so things have to be made to look right and fit.

Reply to
Dave Liquorice

When my vastly expensive level blew over in a gale on it's tripod I checked it's approximate accuracy thus: I had a 40 foot slab of concrete that I'd set level using it several weeks before the incident. I set a post at both ends. set the laser spinning, then measured from slab to spot at both posts. It was bang on :) Initially it wasn't working at all, the shock had dislodged an internal connector - luckily that was easily sorted.

Andrew

Reply to
Andrew Mawson

This is a spot laser?

Reply to
Tim Watts

Invert, not flip left to right.

Hence my qualification about if "its the type that looks like a level"...

One of mine is just that - a conventional level about a foot long, with a LASER that projects from one end.

Reply to
John Rumm

Yup that is what I was referring to for my first option. Just make sure the level bit is level, mark the spot, and then turn it over to see if there is any angular mismatch between the beam and the physical box section.

Reply to
John Rumm

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