Laser Level/Builders Level...

[saveasteading]

On 18/06/2022 at 10:02, SteamyTea said:

Curvature of the earth would render a laser level 3mm out at 200m I think. Unless the world is flat of course

Plane or geodetic surveying.

 

You can imagine the error then on a length of motorway. I did that as a job one Highland summer over a length of 13 miles, through or over forests and quarries and glens. 

Then we just spread the 1m or so error evenly and that was close enough for earthworks.

Nowadays satellites make it somewhat easier.

[SteamyTea]

38 minutes ago, saveasteading said:

did that as a job one Highland summer over a length of 13 miles

The guy who runs they surveying course at Camborne School of Mines was the surveyor in the channel tunnel. They missed, but not by much.

I got the best marks when I did his baby surveyors course.

More about decent record keeping than using the equipment I found.

The theory is fairly easy, the arithmetic basic, but miss read an entry and you can carry that mistake all the way to the grave.

 

 

[saveasteading]

2 hours ago, SteamyTea said:

School of Mines

I was taught by a mining surveyor too. I thought I was good until the new regime was taught. I wont bore with the details but the inaccuracies inside even the best machines was one of the principles.

And how to set  up a theodolite on  a hillside, with no plumb.

2 hours ago, SteamyTea said:

miss read an entry

Road not pointing at the bridge could have been costly, but in a dream I learnt to go and check the day before's work.

 

It is all far too precise for housing, which is perhaps why I am so shocked at the errors that are clearly standard, and overcome at the next stage.

I think our project's recent 8mm level error was probably in setting up the masonry at the corner.. Using the up-a-bit/ down-a -bit method rather than reading a staff or a line.

 

[Tom]

5 hours ago, saveasteading said:

Against it... With the trailing pipe full of pressurised oil, any damage is terminal, and it can't be used where vehicles or even pedestrians may pass.

In practice, I found I had to recalibrate often, especially if the sun was out, as it would read wildly wrongly when it got hot or cold.

Nobody else in the business had the slightest interest in it, so it seems that it works for you or it doesn't.

 

So jut watch that last issue and you should be fine.

 

 

Helpful observations, thanks. The instructional video for the Ziplevel shows the cord being driven overv and all good, but I guess best avoided. Re calibrating - can be done quickly and easily with the provided extendable pole as I see it, so no great shakes, but, yes, something to be aware of in changable weather etc