Laser level recomendation

[SteamyTea]

You can just put one mark on the wall at the height you want, set the laser up as close to it as you easily can.  Measure the distance from the laser line and the mark and the measured height difference, a distance away.

Then join the two marks.

Edited May 7, 2022 by SteamyTea

[MJNewton]

1 minute ago, SteamyTea said:

You can just put one mark on the wall at the height you want, set the laser up as close to it as you easily can.  Measure the distance from the laser line and the mark and the measured height difference, a distance away.

Then join the two marks.

 

It sounds like you are talking about something different.

 

We were discussing about the desire to be able to set a laser level on the floor and have some form of 'beam adjustment' to adjust its projected height so as not to have to raise/clamp the level itself at the desired height. You can't do this, or at least not without accepting the consequences (or breaking the laws of physics).

[Nickfromwales]

8 minutes ago, MJNewton said:

 

Absolutely yup.. 🙂

 

You can't project a horizontal line with a non-zero vertical inclination. 

 

Probably easiest to illustrate with a diagram, but quicker with trigonometry:

 

Let's say you want to hang perfectly level pictures 1.5m up on a chimney breast and in an adjacent alcove, 0.5m set back. With your laser level clamped to step ladders at 1.5m up, 2m from the chimney breast and vertical inclination at self-level of 0° then according to trigonometry vertical delta = distance from wall x tanAngle = 2 x tan0 = 2 x 0 =0. Keeping the level where it is, the vertical delta for the alcove = (2 + 0.5) x tan0 = 2.5 x 0 = 0. Both the same.

 

Now put your level on the floor, 2m from the chimney breast again and adjust its 'beam adjustment' (if it had one, which it won't! ;-)) to point up to the 1.5m point up on the chimney breast. The vertical inclination is tan^-1(1.5 / 2) = 37°. That same line, projected into the alcove, will sit at a height of (2 + 0.5) x tan37 = 1.88m thus 38cm higher than on the chimney breast.

 

Sure, you can mitigate the offset by moving the level further away, but even 5m away if you're keeping it on the floor then the lines will still have a 15cm difference in height.

 

(Saturday night's eh? Rock and roll!)

 

Edit: Figures updates since first post.

Crikey. I need more beer. That’s more maths in that paragraph than. I’ve encountered in the 30 years since I left school  Blue Peter badge on its way as we speak lol.

 

No, it’s still a NOPE. Take it from someone who has owned and used a range of lasers for a very long time.

 

For clarity, before we get our handbags a-swinging…..

The question was about lifting the line up / down, and with some lasers they come with a bracket with a rack and pinion mechanism which allows you to fix the bracket and then tweak the beam up or down + / - 40mm ( whilst not tipping the laser back or forth ). You are correct that the beam would give 3 different plains, sides and front climbing, levelling, and climbing back down again.

 Why do I know? Because I bought a cheap laser back in the day and tiled a bathroom ( a bloody big bathroom too ) and the chuffing laser ( el-cheapo ) hadn’t levelled itself as the manufacturer promised it would. Tiles ran uphill 25mm over 6m. I kept quiet, and I imagine they’re still the same today. Oh, to be young. The room was so long and narrow it was lost in the natural perspective and nobody noticed, complimenting me on my laser and how cutting edge I was………..

[Nickfromwales]

9 minutes ago, MJNewton said:

(or breaking the laws of physics).

I’m always up for a challenge.  

[SteamyTea]

10 minutes ago, MJNewton said:

sounds like you are talking about something different

Maybe.

But if I wanted to easily set up a new level without moving the laser, below is what I do.

Just measure a distance and displace it to the left or the right.

[MJNewton]

 

3 minutes ago, Nickfromwales said:

Crikey. I need more beer. That’s more maths in that paragraph than. I’ve encountered in the 30 years since I left school  Blue Peter badge on its way as we speak lol.

 

 I never did get one as a kid.

 

Quote

No, it’s still a NOPE. Take it from someone who has owned and used a range of lasers for a very long time.

 

For clarity, before we get our handbags a-swinging…..

The question was about lifting the line up / down, and with some lasers they come with a bracket with a rack and pinion mechanism which allows you to fix the bracket and then tweak the beam up or down + / - 40mm ( whilst not tipping the laser back or forth ).

 

Yes, absolutely. But as you say what you're doing there is adjusting its vertical height but without changing the angle...

 

However, *this* was the suggestion/desire being stated (apologies @Temp, this isn't personal - what you said would indeed be a great feature if it could work!):

 

9 hours ago, Temp said:

The main feature missing from the cheap ones like mine is the ability to move the horizontal line up and down. This means if you want to level a curtain rail the laser level has to be mounted at the same height on a tripod or similar. Some come with a bracket for fixing to a wall or similar but it would be a lot easier if the level could be placed on the floor or a table and the beam adjusted to move the horizontal line up and down.

 

If the level is on the floor then it's going to be quite some rack-and-pinion mechanism to lift it up, say, 1.5m in my picture scenario! To get it that high up you'd need to change the beam angle which, as I illustrated, has knock-on consequences hence why no such feature exists.

 

[MJNewton]

9 minutes ago, SteamyTea said:

Maybe.

But if I wanted to easily set up a new level without moving the laser, below is what I do.

Just measure a distance and displace it to the left or the right.

 

Yes, absolutely. And of course that method would work if the level is on the floor in my pictures scenario but you'd be measuring 1.47m (assuming the laser sits 3cm above its base) up from that skirting-level mark which then likely introduces other issues!

[Nickfromwales]

 

Its going to be a long night lol. 
More Cornish liver oil is required. 

[SteamyTea]

1 minute ago, MJNewton said:

but you'd be measuring 1.47m (assuming the laser sits 3cm above its base) up from that skirting-level mark which then likely introduces other issues!

I would use a decent rule, not the ruler in the picture (that is one I had at school, so probably 50 years old now).

Accumulative error is a problem, but this is for a house, not precision engineering.

If you fit, say that curtain rail dead level, it would show that the ceiling isn't, or the windows.

Really just a case of creating a datum and working from that as best you can.

[SteamyTea]

7 minutes ago, Nickfromwales said:

 

Its going to be a long night lol. 

The head looks level.

 

Short night for me, alarm set for 4am.

Edited May 7, 2022 by SteamyTea

[MJNewton]

Leaving the maths where it belongs and bringing my input back to something more constructive, a vertical 'trim' adjustment like @Nickfromwales's level has *is* one thing I do wish I had on mine. Whilst not essential given you can introduce a measured offset like @SteamyTeashows, my OCD does mean I am far more comfortable having the laser line on exactly my mark/hole/whatever and so I end up making minor tweaks to my clamp which is often far from ideal... Up a bit, down a bit, back up a bit, damn slipped beyond the max angle start again, type of thing.

Edited May 7, 2022 by MJNewton

[MJNewton]

1 minute ago, SteamyTea said:

The head looks level.

 

Aha, but does it?

 

With the camera angle such as it is it's not really possible to determine whether it is level front-to-back for the reasons I was covering. Time to get the level out @Nickfromwales!

[MJNewton]

My 1000th post!

 

(And to think here I am: Saturday night doing trigonometry on the subject of laser levels. Is this what my life's come to?)

[Nickfromwales]

8 minutes ago, SteamyTea said:

The head looks level.

 

Short night for me, alarm set for 4am.

So you can get an early start checking for whether I said KwH or kWH or anything else i can do to keep you from relaxing.

K-Wh

[Nickfromwales]

2 minutes ago, MJNewton said:

My 1000th post!

 

(And to think here I am: Saturday night doing trigonometry on the subject of laser levels. Is this what my life's come to?)

Times that by 22 and you’ll realise what a real problem you have……..

[Nickfromwales]

2 minutes ago, MJNewton said:

My 1000th post!

 

(And to think here I am: Saturday night doing trigonometry on the subject of laser levels. Is this what my life's come to?)

And congrats on popping your 1k cherry  

[Onoff]

31 minutes ago, Nickfromwales said:

 

Its going to be a long night lol. 
More Cornish liver oil is required. 

 

Is that on draught wherever you are? Only ever had it bottled. 

[Nickfromwales]

10 minutes ago, Onoff said:

 

Is that on draught wherever you are? Only ever had it bottled. 

Yes, yes it is.

There’s a magical, almost mystical fountain of youth that it pours out from. The more In drink, then less old I feel.,

”All hail the ale”.

[SteamyTea]

5 hours ago, Nickfromwales said:

K-Wh

 

[Nickfromwales]

5 hours ago, SteamyTea said:

 

Watt hour were you up until?

[SteamyTea]

39 minutes ago, Nickfromwales said:

Watt hour were you up until?

Not late.

But at my mother's now.