String Levels

Not sure where to post this so I thought I would try here. I'm trying to use a string level to determine the pitch of my yard so that any water runs towards a catch basin I had installed. Here's my problem. I'll center the bubble near one end of a 15 ft string and double check it by turning the level 180 degrees. Now when I go to the other end the bubble should still be centered, right. Well it's not, it's off by quite a bit. I have a couple of levels and they all do the same thing. I don't understand what I'm doing wrong.

DLH

 

Unless your string is as tight at a guitar string, it will sag over distances and not give a good reading. If you are having to be that precise, you may want to purchase or rent a rotating laser level with a receiving unit to determine pitch.

 

I have purchased some inexpensive (about $40) line lasers that work well. They are just not as bright as the more expensive ones. I have used them at dusk with good success.

 

A string level only works if the level is places in the center of the string.

When you place the level near the ends, you are measuring the slight slope near the ends due to sag in the string. Place the level at the center (7.5 ft for a 15 ft. string) and you should be fine.

 

IMO you'd be better off using a transit to set strings when dealing with long distances. This way you're directly setting pitch off the tape measure referenced to a single level reference (the transit bubble) rather than relying on reading a dinky bubble in a $2 level, in several locations, and then dropping to your pitch. Should be cheap to rent one for a couple hours.

 

Sorry, I didn't reply sooner. Spent 5 days in the hospital with an infection in my neck.

Wirepuller38, I'll try what you suggest and see what happens.

I have one of those inexpensive laser levels and have found it to be a pain to get the bubble level. Earlier this year I had the opportunity to see commercial laser lever being used, it worked great. Just set it on the ground and turn it on. So, if need be I'll look into renting one.

DLH

 

I wonder if a water level would work? Using a Water Level

 

Bingo! A water level will be dead on accurate, and a lot less expensive than my $200 self leveling laser level with receiver. I find myself using a water level if I suspect the distance between the laser and object may be too far and in error.

 

I have a 50' water level. I bought it probably 20 years ago. They've been around for thousands of years and they are very accurate when used right - and they are really easy to use right.

Head to a big box and buy some clear plastic tubing.

 

Even though it's a stale thread, here's my take on line (string)) levels:

Their simplicity is what makes them so practical and functional. No messing around with water, or cussing at the laser because it's not bright enough or the battery is dead (again). I've used line levels for more than 40 years, and never had a problem.

The thing to remember is to pull the line absolutely straight and tight. I always use nylon mason's line, which stretches considerably when placed under the correct tension. Can't just pull it bare-handed, either, because it will cut right into the skin of your hand like a knife if the tension is where it should be--always wear a pair of snug-fitting leather work gloves. If not using batter boards, a paving pin, piece of scrap rebar or wooden stake is required at each end, driven into the ground deeply enough to not move when lateral pressure is applied. Then loop one end of the nylon line around one pin using a mason's slip knot (no tying necessary, the line tightens against itself) before proceeding to the other pin, where the tugging contest begins. Using both hands, pull the line tight while looping it around, then pull it again and again, tying it off with another mason's slip knot only after the line has ALL of the stretch taken out of it. Meaning there is absolutely no sag when sighting along it, but rather a perfectly true, straight line. Place the line level anywhere on the line, and the bubble will always read the same.