Stone masons of the guilds in Europe relied on plumbs and plumb levels in their work, and the importance of these and other tools has carried over symbolically into Freemasonry. Many of the finest brass plumb bobs are from England. Note the amount of decoration on all of these bobs. Figure 2 shows a whale bone bob to the left of three ivory ones. Figure 1 shows Bruce with some of the bobs that occupy a wall in his home. There are little bobs for clockmaking, large bobs for shipbuilding, bobs for special purposes, and bobs with exotic shapes and extraordinary hand-done decoration and filigree. Collectors have bobs of ivory, bone, pottery and wood. Several catalogs had the same selection suggesting a common manufacturer.īut not all plumb bobs of this period were so mundane. Steel points were offered with some bobs and japanning was offered with some iron bobs. Most bobs offered in this general market were heart shaped, with an occasional turnip shape, and were made of brass, lead or iron. Symmetrical construction to assure the plumb bob would hang on its central axis, affixing the line on the central axis with the point, and the point itself were the improvements that brought us to the bobs we find in American hardware catalogs of the 1800s (Shannon, Walter's, Russell & Erwin, Hammacher Schlemmer etc.). The plumb bob evolved to meet requirements for accuracy in such functions as erecting tall buildings, installing machinery, mining and surveying. Illustrations of early plumb bobs appear in the December 1992 issue of The Plumb Line. An early improvement was the drilling of a hole to attach the line. Such crude bobs, with no thought yet of a point at the bottom, offered sufficient accuracy for their purpose. These very early bobs were simply shaped stones, sometimes with grooves around them to keep the line from slipping off. So I want to thank Bruce for sharing his knowledge and providing the photos for this article.Įgyptians certainly used plumb devices to build the pyramids, and perhaps others used them earlier. Bruce is General Manager of News Channel 15 in Fort Wayne and an avid plumb bob collector. Made of brass, they are corrosion-resistant and durable as well, perfect for use in tough field conditions.This article takes its inspiration from several phone conversations with Bruce Cynar of Fort Wayne, Indiana and from his publication The Plumb Line. They also feature screw caps to accommodate extra steel points in which users can feed the string. The plumb bobs that are available here on Engineer Warehouse won’t be difficult to set up since they weigh from 12 to 24 ounces. Since it makes use of gravity and weighs down the string, the string then serves as the reference line. When it stops swinging, you can finally establish the point or use the plumb bob as a vertical reference. Then, suspend the plumb bob and let it hang freely. To use the plumb bob, it must first be attached to the end of a string. It can also help find the nadir or the direction pointing towards the ground below a specific location. Aside from helping in setting up instruments, it can be used to check if surfaces are perfectly plumbed or vertical. This weight, which is often suspended from a plumb line, serves as a vertical reference line. Whenever surveying instruments need to be placed over precise survey markers, the task often calls for the use of a plumb bob.
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