A plumbing fork is a U-shaped piece of metal or wooded frame (Figure 33.4). The end of one of its arm is pointed and the other arm is having an arrangement for hanging a plumb bob. The frame is constructed in such away that the tip of the pointed arm and the plumb line lie in the same vertical line. At the time of use, the pointed arm is placed on the table and the other arm, with a plumb bob attached, is kept below the table. Plumbing fork with a plumb bob is used in large scale surveying for Centring of plane table and for Transferring of ground point.
Figure 33.4 Plumbing Fork