What spirit level?

[dent]

Hi all,

I'm about to build a small block extension, and need a longer spirit level than I currently have. Firstly, what is a good length - 1.2m or

1.8m? I would think 1.2 is easier to wield, but would a 1.8m be better for longer runs? I'd rather spend the money on one decent level, than have to get two of different lengths. Secondly, I think that Stabila and Stanley seem to be the main makes to look for - is there anything to differentiate between them? What features should I look for?

In the high-tech world of digital spirit levels, self-levelling laser line projectors and so on, is it worth considering anything more than a simple spirit level, either as a replacement for the level, or to be used in combination with, to make the job easier?

thanks,

dan.

[Matty F]

The short level that you have is adequate for window sills etc. Even a 1.8m level is too short to get the floor level. Use a water- filled piece of hosepipe with a plastic bottle at each end to get levels right.

[Tim S]

dent coughed up some electrons that declared:

I've got this set:

bad. Not as good as a super quality level (the bubble is smaller than the gap between the lines) but I find it adequate.

Having a 2', 4' and 6' level is extremely useful.

For longer range work, I find a basic laser level very useful - I have a cheap Stanley cross-line laser from ebay for 90 quid (double that if new).

The downside is that you cannot see the red line outside - though you could set up and mark up in the evening.

For wall work I've used all 3 levels and a laser, and for flooring I've used

4', 6' and a laser.

If you fancy something more expensive, a green crossline laser will be more visible.

I think the spirit levels are a must have, but a cheap set are adequate. I would not be happy without my laser though. Having 3 lines set at 90 degrees from each other is extremely useful. On occasion I could have found a use for a plumb laser but not often enough to warrent buying one.

Cheers Tim

[Ian White]

I got the 4ft level from that set, basically the cheapest one rated at

0.5mm/m. It passed the usual turnaround test very comfortably. Used with care, it proved accurate enough for levelling around all four walls of a room (although some of that must be thanks to cancellation of random errors).

The main objections are that the plastic handgrips bulge out too much, making it more difficult to use the level on its side as a straight-edge, and the plastic end buffers are a different size from the aluminium I-beam. (A few minutes with a milling machine will fix all that... someday.)

You couldn't trust the projected horizontal or vertical lines at a distance because the lenses have some spherical aberration which causes the lines to curve. It is much more accurate to use the spot beam to transfer some reference marks onto your distant target and then continue the local marking-out with your good bubble level. With a short, cheap laser level you'd definitely need to turn the level around and do some averaging, but the spot beam is much brighter than the lines and can be used in bright sunlight.

[NT]

take a piece of planed timber, sit spirit level on it in the centre, there you go one long level.

NT

[Andrew Gabriel]

1.2m is fine. When leveling longer lengths, remember to reverse the level each time, so any error in it cancels out rather than adds.

You'll also want a short (e.g. 12") level for checking across tops of brickwork, where a long level is too unwieldy to be accurate.

I use simple spirit levels, and pins and string. If a laser level had a power boost button to cause it to burn a mark or a line, then it would be useful;-)

[Limey Lurker]

the lines to curve.

Really? How the Hell does that happen, then?

[1501]

Presumably, close proximity to a black hole.

[Tim S]

Limey Lurker coughed up some electrons that declared:

He means the line, along its width. Not its length.

I never considered that, but then I couldn't work that accurately anyway, so it's fairly moot for me.

[Ian White]

No, I really did mean that the line is curved along its length on the wall.

Apologies that "spherical aberration" wasn't the correct term for the cause, but it's still in the cheap and nasty optics.

The laser diode initially creates a spot beam. The flat fan beam that projects a line on the wall is created by a cylindrical diverging lens. You'll only get a straight line if the axis of that cylinder is exactly at right-angles to the beam. If the lens is tilted either forward or back, the flat fan becomes slightly dished and the projected line will be slightly curved.

My cheapie laser level projects a very noticeable curve relative to a plumbline. OK, we can't expect much better for a retail price of under

20 quid (which means the optics probably cost about tuppence) but even I can hang wallpaper straighter than that.

[Tim S]

Ian White coughed up some electrons that declared:

We're talking at cross purposes. I meant curved across the wider width of the beam fan, which is the same as what you're saying Ian.

Not along the radial length of the beam, which of course would need a large gravitational field to achieve :)

That's a good explanation.

I must check mine out of interest now.

Cheers

Tim

[Jules]

Or a very fat person. Careful the level doesn't fall into orbit around them.

[Tim S]

Jules coughed up some electrons that declared:

Interestingly I've just checked my 4' Forge Steel level and it's miles out on a reversal test.

It's been abused and I usually use it as a straight edge and for rough jobs (because it's cheap), so not sure if it was always dodgey.

My Wickes 2'er is bang on though and so, by cross checking is my laser.

Cheers

Tim

[Jules]

Hmm yes... interesting that they can go out of calibration. I suppose if the glass envelope is short and only supported at the ends, any tiny change will put it way out.

I've got a big ol' 4' level back in storage in the UK - must get it shipped over sometime. I'm surviving on a 2' plastic-fantastic one here (plus the little one built into my set-square).

Laser? How posh and new-fangled of you. ;)

cheers

Jules

[Harry Bloomfield]

Ian White pretended :

I paid £19.99 for mine, with not much in the way of expectations of its accuracy from me - but I just cannot fault it even over 30 feet, when compared to a water level or Stabila. It came with a tripod, you fix the head on the trip release the internal bob weight, then turn on the H V or both beams. You don't need to set it up, so long as the tripod is roughly level it will do. I used it to build a small extension, with string lines between for getting the courses straight, tiling and a few other tasks over the years - much easier than a level.