A Lot - also plumb , plumb line , sinker or plumb - is a tool for determining the perpendicular direction and determining the perpendicular or vertical .
A traditional solder consists of an axially symmetrical piece of metal called lead attached to a thin string. There are special plumbing instruments for greater accuracy, and for measuring zenith distances there are vials built into the theodolite or the plumb sensor ( compensator ).
The metal piece ideally has a high specific weight (“heavy”); it used to be made of lead . The reason for this is the lower sensitivity to air currents. However, this reduces the damping of an initial, unwanted movement of the solder. The solder body is cylindrical or conical with the tip pointing downwards. The tip serves as a pointer under the attachment point. The string pulled tight from the piece of metal runs exactly along the vertical . With a longer such a plumb foot points can be "abgelotet", but what is usually visually today.
In geodesy , the plumb bob is used to centrally set up older theodolites and alignment poles over the measuring points, surveying or fixed points . Newer devices have a process for this range pole , an optical plummet or a laser plummet .
- The plumb bob is rarely used. It used to be used to set up almost everything from a range pole to an instrument tripod vertically . The plumb bobs used are made of iron or brass , are pear-shaped or elongated, weigh 200–500 grams and have a plumb line length of around 2.5 meters.
- The optical plummet is an additional device for precisely centering a measuring instrument over a point on the ground. It can be a stand-alone instrument or a tripod ( tripod ) or theodolite be incorporated. A target mark in the plumb bob's eyepiece is deflected on a switching prism exactly to the zenith or nadir and brought to coincide with the ground point (or a zenith point).
- The laser plummet is an independent accessory or is already built into the theodolite. It replaces the optical plumb line with a laser beam. The brightness of the laser is adjustable.
Centering accuracies of the individual plumb bob types (in calm conditions and 1.5 m instrument height):
- Pole: 1.0-2.0 mm
- Plumb bob: 3.0-5.0 mm
- Optical plumb line: <0.5 mm
- Laser plummet: <0.5 mm (with a laser diameter of 1.5 mm)
Precision solders achieve accuracies of 1 mm at 100 m.
- Mason's cord
- Plumb line (shipping) , level (water level measurement ) , light plumb line
- Dummy solder
- Swimming plumb bob
- Perpendicular deviation