How to make a lot level

Interesting how a question about leveling a lot turns into a debate about the merits of a water lever! - damn Engineers! I recently bought a Porter Cable self-leveling laser for $100. It is great for projects like this. I use it mostly, however, when investigating settlement and sags in houses. Best $100 I ever spent. I may go for one that continuously spins next time.

Rob Munach, PE

Good idea except for one thing ............. A string line with a level on it sags after a short distance ..................

Steve

Nothing you'll ever notice in a 30' pad with a 6 foot rule......... and a tightly stretched line. How many houses do you suppose are set out this way?

This is how I make a water level. Get 3/4" brass fittings like your going to replace the ends on a hose and put them together with a new rubber seal. Get an extra male one and drill a hole on the side next to the bottom of a plastic 5 gal. bucket and epoxy it so the barbs are pointing out. Get about 3' of clear hose and cut it in half then connect to the fittings and then to the bucket after the epoxy is set. Use only good hose between the fittings to extend it.

To set it up , elevate the bucket on something that won't move and lay out the hose as straight as possible and hang up the end above the bucket. Fill the bucket all the way up and look at the water. If it is cloudy from very small air bubbles drop the end and force water through the hose and hang it back up. Fill the bucket back up and wait till the water is clear then drop the end as low as possible till it has all new water in it. If the water was clear then dropping the end and forcing water down the line will do , but always run new water through it just from gravity to make sure the big bubbles are out.

To use it , mark the hose so that you use the same part of the hose. For example if you use different parts of the hose you'll be changing the level by a couple of ounces. Hold the hose up against a wall , stake, pole , ect. and stop the water from bouncing with your finger on the end at the proper times. Then mark everything to where ever the water is. Measure up or down from those marks or use a stick to transfer while your leveling which is the PITA way.

Do not step on the hose, kink it , coil it up , leave you finger on the end, move the bucket , or let the water evaporate. I don't like the two person method. One chases and the other marks and you have to trust the other person. I've had all kinds of problems that way from co-workers dicking with ya , dropping the hose, ahhh that's close enough while its still bouncing , forgetting to take their finger off the end , ect... Double check the first mark when your done and do it all at once. In the summer if you take your time bubbles will form from the heat. Speed is your friend , no stopping. Set up all your marking spots before you set the level up.

Wow , this is a pain to explain something so simple. I do it all the time if anyone has a question. Works great for all kinds of things like cutting the tops off the poles. The roof of my shop was done that way and it only slopes about 2" in 15' by design.

I wonder if things like the bases of pyramids and tops of aqueducts are curved like the earth or straight. Off hand I would think they would have to have optics to get it straight. Bet they are curved. Even line segments would be interesting. Things that make me go hmmm... Structures should be straight and aqueducts curved. Then again suspension bridge towers wouldn't be parallel. Anyone know off hand what one degree would be in miles at sea level? That's one of my favorite curves to view , at the beach.

This was just being discussed over in one of the misc.transport.rail.americas The Verazano Narrows bridge between Statin Island and Brooklyn has towers the are about 2 inches further apart at the top then the bottom because of the earth curvature.

On Tue, 20 Apr 2004 11:30:55 -0400, Glenn Ashmore vaguely proposed a theory ......and in reply I say!: remove ns from my header address to reply via email

Agreed, and important, but oft forgot (DAMHIKT!)

But the _height_ is not necessarily there if you then take another "level" from the middle of the string.

**************************************************** I went on a guided tour not long ago.The guide got us lost. He was a non-compass mentor.........sorry ........no I'm not.

On Tue, 20 Apr 2004 14:40:16 GMT, Rob Munach vaguely proposed a theory ......and in reply I say!: remove ns from my header address to reply via email

Gee! When I had my settlement investigated, the lawyer only read the first _page_ for $100! ..........oh.....sorry.

A question if I may. How good are these things in sunlight over distance? Are there staffs that have sensors, or is this not needed? As usual we are way behind you guys in pricing, so until very recently these have been way out of range. They are starting to get there, and I am certainly looking at one, but I am worried that economics and laws about lazers may cause weak visual behaviour.

Thanks

**************************************************** I went on a guided tour not long ago.The guide got us lost. He was a non-compass mentor.........sorry ........no I'm not.

On Mon, 19 Apr 2004 13:32:52 -0500, jerry Wass vaguely proposed a theory ......and in reply I say!: remove ns from my header address to reply via email

Years ago I actually made and used a "water level" It used plastic tube, on a piece of aluminium square about a meter long. The tube stood up at both ends and was filled with water with ink on it. I had it on a tripod. You could sight along the water levels and get surprisingly accurate results. Sort of a bubble level in reverse!

**************************************************** I went on a guided tour not long ago.The guide got us lost. He was a non-compass mentor.........sorry ........no I'm not.

Not too many anymore - most are shot with a transit. And the ones that were set with a line level could be shot with a transit and you would see the error. They will get you "kinda close" but every time I ever had to use a string level, I would always take several readings, sliding the level back and forth to the same position, re-read, etc. Most line levels are only about 2 or 3 inches long, and most are made cheaply, and they are surely not something I would set a house with. If a good transit is not available - the water hose would work, although cumbersome. Ken.

I would fathom a guess that hot water is "lighter" than cold water, therefore if you had a 100' of hose, and one end of it is in 25' of direct sunlite (and had been for a period of time) about 20 degrees hotter, the colder water would push the hot water a little higher in the tube... dunno ... never experimented ... If you initially held the sight tubes side-by-side and leveled the water and marked the tubes... then stretched out the 100' of hose (some in sunlight, some not) and staked the sight tubed into the ground to measure from the sight tube marks down to the dirt, I would imagine, after a period of time, that it would be possible for the "hot" end to be higher than the sight tube marking, while the other end may be a little below the sight tube marking. Ken.

I have not used it in bright sunlight yet - but I have heard that it can affect it. Also, the beam isn't likely to be powerful enough to be seen at a distance in bright sunlight. Hey, what do you want for $100?

I

Hi Nick, I bought one of these,

connection, just happy with mine. I can see it maybe 25 meters in sunlight using the red tinted glasses that come with it. I just turn it on and walk about with a staff I made from a tomato stake witn the blade out of a $2.50 tape measure nailed to it, it works very well.

Just to prove the point Rob made about damn engineers, I don't trust water levels because they level to a curve about the the same as the radius of the earth, where a laser is flat. LOL

regards,

John

On Wed, 21 Apr 2004 22:37:10 +1000, "john johnson" vaguely proposed a theory ......and in reply I say!: remove ns from my header address to reply via email

hmm. $Aud95!

Ok. I would still rather spend $300 and get a reasonable piece of gear than $100 and get something that disappointsme.

Ok if I ask a few questions?

More to the point. Will you answer them?

I have also just been out and fiddled about with my Class II pointer and may have some ideas.

(1) If you can make a shade for the staff, with both top and side shields, you can significantly increase the visibility. You would need to turn the staff so that the side shileds kept the sun off. There are a couple of spots where this would not work, of course.

(2) 3M make reflective film. I have some red stuff. That really makes the lazer point stand out. May even be a safety issue for a static lazer.

I hate ebay....however, it certainly seems to be reasonable and if it's OK up to 25m that's not bad!

So you are close to the staff, and can see the laser stripe on it, I guess. I can see where that would work. I have a laser pointer, and in sunlight I can't see the point if I am _at the laser_ and the beam is more than 10 metres away. At night, I can see it against a wall 250 m away!

I was assuming I was going to need to point, locate and mark. Of course with a rotating bizzo, you can walk around and see the beam.

What rotation speed do you use? I am interested because I would assume that the faster it turns, the quicker it wears.

Does it take rechargeables? What capacity and whow long does a set last?

How do you set the thing level? Bubble? Auto?

Have you done an "back checking" on its levels to see how accurate it is? By this I mean actually marking a level that it gives, then marking its own level, placing it at the new level and seeing it sends back to itself.

How big is the spot?

.....with a "thin spot" in the middle of the "run"?

**************************************************** I went on a guided tour not long ago.The guide got us lost. He was a non-compass mentor.........sorry ........no I'm not.

On Wed, 21 Apr 2004 10:26:54 GMT, Rob Munach vaguely proposed a theory ......and in reply I say!: remove ns from my header address to reply via email

Not much for $100. But then I didn't think we had stuff for $100! I see we do.

But I would hate something that simply did not work, or restricted me badly. I would pay more to avoid that. I may not need to.

**************************************************** I went on a guided tour not long ago.The guide got us lost. He was a non-compass mentor.........sorry ........no I'm not.

Hi Nick, Reply below each question. regards,

John

I'll try!

I'll check it out again in the daylight tomorrow arvo, make sure I'm not leading you astray.

It's great, I have a little cowley automatic level, but it needs two people to use it, this thing is easy by yourself.

Rotation speed is adjustable, the faster you make it the duller it gets, smaller range. You can slow it down to less than a rotation per second, but it still wizzes past pretty quick at 20M

As far as wear goes, the rotating bit is very light (no pun intended) and lightly loaded (and again) , I think it will out last me with the occasional use I will give it. If you wanted to use one every day I'd be spending a lot more on a professional model. I just bought it to map my sloping yard, so I can work out where is the best spot and shape for my new shed, then level the site and form work etc.

It takes three AAA cells, I'm still using the set that came with it about two months ago but I haven't used it that much. You could put rechargeables in it, but it comes with alakaline batteries. The book says it will run for three hours on set of batteries. That would do a lot of leveling, because you can turn it off without disturbing it.

It has two vials, you adjust the screws underneath to get the bubbles centered. I found it a bit difficult to get the bubbles centered, the vials are very sensitive, the screws are a little coarse.

Yes, I ran a set of levels from one side of my yard to the other, marked the level on few things across the yard, then set it up on the opposite side of the yard and did it again. The error was around 2.5mm across 20M of yard, I was impressed! It's rated accuracy is +- 5mm over 10 M, so it was better than I thought it would be.

While I had it there, I went back and readjusted the bubbles in the vials to try and get some idea of the sensitivity, and convinved myself that it would be repeatable to get this sort of accuracy.

One thing that worried me, and I haven't fully tested yet, was that the laser has to be at 90 deg to the axis of rotation, or it will project a shallow cone rather than a flat disc. The test I did above came at the same marks from different angles, not a straight line through them, so it did test this a bit?

It's at least as accurate as letting my wife read the stall with the cowley level! LOL

Close up it's about 2.5 mm, across the yard it grew to about 3.5 mm. Its not really a problem though as the edges are clearly defined and it's easy to judge the centre of the dot.

Another thing, it has a bracket at 90 deg to it's base mounting, so you can clamp it to things and use it to set up flat planes that aren't level. I've used it to 'draw' some straight lines down a model A chassis I'm working on. It's better than a string line because it projects a plane rather than the single line of the string.

At temp T (F), it weighs about 62.46-0.01(T-68) lb/ft^3.

Imagine filling a 110 foot x 1 ft^2 hose filled with 100' of 68 F water. The water weighs 100x62.46 = 6246 pounds. Now heat half of the water (3123 pounds of it) to 88 F. A cubic foot of the warmer water weighs about 62.26 pounds, so the warmer water now occupies 3123/62.26 = 50.1606 feet of hose, ie the hose now contains 100.1606 feet of water.

Imagine hanging one end from the shady side of a 50 foot tall building at

68 F and hanging the other end from the sunny side around a corner. We might see water column heights Hc and Hw, where Hc + Hw = 100.1606 feet, and 62.46Hc = 62.26Hw, which makes Hc = 0.9968Hw, so 1.9968Hw = 100.1606, and Hw = 50.1606', and Hc = 50', and Hw - Hc = 0.1606 feet, or 1.927 inches.

If all the hose were on level ground, we wouldn't see any height difference, although both heights would rise by 0.9636 inches, or more, if air bubbles undissolved from the warmer water.

Nick

On Thu, 22 Apr 2004 19:57:10 +1000, "john johnson" vaguely proposed a theory ......and in reply I say!: remove ns from my header address to reply via email

Thanks for all of that! I will chew this one over. I may check out more expensive models, and see what I am getting, or if there is a "middle road" )some of them are a couple of grand!)

Talking of accuracy. When I have help my FIl lay out pads a couple of times, using a dumpy, I used to get really pissed off. I would tap in a peg, and p8ut the staff on top and he'd say "down a tap" and we'd go again..."up" (pull) "down" (tap) etc etc. We would have been talking

0.5 mm ? I have to suppose he worked to edges of the markings on the staff!

Mind you, I have never seen more level pads thatn that guy did. Scary. When you wet them down after laying, and kept them wet, there was _never_ a pool anywhere.

**************************************************** I went on a guided tour not long ago.The guide got us lost. He was a non-compass mentor.........sorry ........no I'm not.

Others have suggested the best cheap solution, a water level. I'll add one more tip. If you need to take the level along a line, say, to check the level of the pad out in the center, do it with a cheap laser. Any laser can work, even a cheap laser pointer, as long as you can affix it securely.

The method is to aim the laser across the worksite at a convenient height. A cheap laser level is handy because it has a tripod socket. The level the beam using the water level. One end at the laser and the other end on the far side of the worksite. Once the beam is level you can shoot vertical distances at any point along the beam using a simple steel rule. Or even a string with a mark at the laser impact point. Just touch the ground with the rule and observe where the laser grazes it.

Most cheap lasers have too much beam spread to use the spot so use a grazing contact, say, on the bottom of the beam. My rule is magnetic and I have a cylindrical magnet that I can roll along the rule until the laser just barely illuminates the edge.

John