![]() It is typically made of stone, wood, or lead but can also be made of other metals. It is a precursor to the spirit level and used to establish a vertical datum. Plumb Bob and Set Square, symbols of accuracy and trueness, from ancient Egypt. Some bobs have pointed tips that can be bent by repeated use or abuse if the point on yours is bent or out of alignment, replace it. According to Wikipedia, A plumb bob, or plummet, is a weight, usually with a pointed tip on the bottom, suspended from a string and used as a vertical reference line, or plumb-line. Excavation and foundation contractors rely upon the plumb line, and constructing a chimney the tool can indicate whether a flue is running true vertical or veering off plumb. ![]() Surveyors sometimes use plumb bobs for lining up points or transferring them. The plumb line in one place can be used to sight an object in another - a pipe, for example - for plumb. Hold the plumb bob in one hand and grasp the crossmember. Once it is hung and still, the top and bottom points can be marked and used as guides. Using the square is like using any other square. For example, you can locate fixtures or decorations in relation to an object or surface below (or above) using the plumb line. This wooden plumb level from the tomb of Sennedjem consists of two short pieces projecting at right angles from a longer slab. A spirit level will also accomplish those tasks, but some jobs are much more easily done using the tool. ing a vertical wall had been solved in ancient Egypt an the use of various tools incorporating a line and weight line and bob. The plumb bob is useful in establishing vertical for a wall in construction or a doorjamb when hanging a door. (Note that the line must be hanging free to get an accurate reading.) The weight, or bob, is then allowed to swing freely when it stops, the point of the bob is precisely below the point at which the string is fixed above. To use the tool, the string is fixed at the point to be plumbed.
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