Sunday, March 2, 2014

SURVEY INSTRUMENTS 03- RANGINNG POLES, ARROWS AND WOODEN PEGS

Ranging poles










Ranging poles are used to mark areas and to set out straight lines on the field. They are also used to mark points which must be seen from a distance, in which case a flag may be attached to improve the visibility. Ranging poles are straight round stalks, 3 to 4 cm thick and about 2 m long. They are made of wood or metal. Ranging poles can also be home made from strong straight bamboo or tree branches. Ranging poles are usually painted with alternate red-white or black-white bands. If possible, wooden ranging poles are reinforced at the bottom end by metal points.

Arrows 



Accompanying each chain are 10 arrows. They are also called marking or chaining pins, and are used to mark the end of each chain during the process of chaining. They are made of good quality metallic wires of 4 mm (8 s. w. g.) in diameter and of a minimum tensile strength of 700N/ mm2. The wire is black enameled. The arrows are made 400 mm in length, are pointed at one end for inserting into the ground and bent into a ring at the other end for facility of carrying. They should have a piece of white or red tape tied to the ring so that they can be made easily visible at a distance. To mark the end of each chain length, the arrow is inserted in the ground, but when the ground is hard, a scratch may be made with the pointed end.

Wooden Pegs 


Wooden pegs are used to mark the positions of stations. They are made of hard timber and are tapered at one end they are usually, 2.5 cm square and 15 cm long, but in soft ground, pegs 40 to 60 cm long and 4 to 5 cm square suitable.

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