The dummy level is simple compact and stable. Dummy level is the most commonly used level. It is cheaper, and easier to maintain in adjustment.
Part of the dummy level
Leveling head
Telescope
Eyepiece
Diaphragm
Focusing screw
Ray shade
Level tubes
Level tube rule
Cross bubble tube
Setting the Level:
1. The tripod legs are spread 1 or 1.2 m and pushed firmly on the ground. The legs are so adjusted that tripod head is fully level in both directions.
2. The telescopic is turned unit. It comes parallel to two opposite leveling screw and the bubble is brought to the center of tube by turning these screws.
Both screws are turned either inward or outward depending on the direction in which the bubble is required to move. The telescope is then turned around until it stands over the third screw. By manipulating that screw, the bubble is brought to the center. The telescope is rotted and brought over the third screw and the bubble is brought to center by adjusting other screws.
The telescope is turned to bring the level rod into the field of vision
Eye piece is adjusted to focus on the cross hair.
The rod is read at the intersection of then middle horizontal cross hair with the rod.
Leveling Rod:
Leveling rod is used with the level to obtain the vertical distance between the plane of sight and the surface or point on which the level rod is held.
Types of Leveling Rod:
Self reading rod.
Target rod.
Generally self reading rod is commonly used. They are usually of 4 and 5m length. The self reading rod is designed to read directly by the man from his level. The rod is graduated in meter, decimeters and centimeter. Reading are normally taken to two decimal points as 6.05, 9.86, etc.