60 oz. Plumb Bob, Late 19th C.

7 1/2" long. Brass with iron bottom, string on brass reel.

Click for a Closer Look The plumb bob is one of the oldest tools in the world. The Egyptians used them for building. The key in a building construction is keeping things square to the ground. Perfectly horizontal or vertical as the case may be. The key to the plumb bob is that the point at the end of the bob is directly in line with the string. For example, when building a brick wall, one mounts the plumb bob above the area being bricked so that the point is over a reference point on the ground. This gives the bricklayer a perfect, taut, vertical string to guarantee that the wall of bricks will be all the same distance from the string and hence be vertically straight. On a construction site, taut strings are routinely used as references and are even chalked and snapped against a surface to leave an accurate line. For the last two centuries or so, plumb bobs have been typically made of brass or bronze with a steel tip. The top screws off so that the string can be run through a hole in the center of the top ensuring that the string is aligned with the tip. Get a closer view of the object (75KB)


PLUMMET, PLUMB RULE, PLUMB LINE is an Instrument us’d by Carpenters, Masons, to draw Perpendiculars withal, in Order to judge whether Wall, Etc. be upright Planes, horizontal and the like. It is thus call’d from Plumbum, I. e. a Piece of Lead, fashened to the End of a Thread or Chord. Sometimes the String descends along a wooden Ruler, etc. rais’d perpendicular on another; in which Case it becomes a Level."

Excerpt from "The Builder’s Dictionary OR, Gentleman’s and Architect’s COMPANION" First published 1734. Reprinted 1981 The Association for Preservation Technology. The original spelling and syntax has been retained in this excerpt.

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