What are plumb bobs made of?

3rd March 2020

What are plumb-bobs made of?
			Shop for Plumb-Bobs
			Being one of the oldest tools known to humankind, the plumb-bob has been made out of variety of materials over the millennia, from simple stone to hardened steel.

			Traditional and antique plumb-bobs
			Traditionally, plumb-bobs were made from stone, hardwood, lead, or bronze. Other models, which were usually reserved for decorative purposes only, were carved from bone or ivory. Plumb-bobs made from these materials are rarely used these days or were never intended for practical use. Just as technology advances and renders older machines obsolete, so it is with these plumb-bobs.

			Modern plumb-bobs
			Much more commonly, the materials modern plumb-bobs tend to be made from are: Brass Steel

			Brass As metallurgy skills increased through the ages, plumb-bobs made from brass became increasingly common, as brass (an alloy of copper and zinc) was cheaper to manufacture than bronze. Brass is used for plumb-bobs as it is a dense, relatively malleable material that resists corrosion and is also considered more aesthetically pleasing than bronze.

			Brass and steel With the invention of steel, plumb-bob manufacturers began adding steel components such as a steel tip to increase accuracy and the longevity of the tool’s use. Steel is prized for its hardness, durability and resistance to corrosion.

			Steel Solid steel plumb-bobs have been in production since the late 19th century. Steel is prized for its hardness, durability and resistance to corrosion.

			Nickel and zinc plated steel Some steel plumb-bobs are given a zinc or nickel coating for increased resistance to corrosion. The zinc or nickel creates an impervious metallic barrier around the steel and does not permit water to contact the steel.

			Which material should you choose?
			Steel and brass are really the only choices for a modern plumb-bob. If you decide to purchase a brass plumb-bob, note that brass is a softer metal than steel and may be liable to becoming dented or deformed if knocked about on a busy site, though brass does have the advantage of being resistance to corrosion from the elements. It’s advisable to get one with a replaceable steel tip for increased durability and longevity.

			Purchasing a steel plumb-bob will give you the advantage of having a strong and durable tool but try and get one with a nickel or zinc plated as this will promote corrosion resistance. The material a plumb-bob is made from is perhaps a little less important than the fact that it is balanced and heavy enough for the job in hand. For more information, see the page entitled: Tips for spotting a top quality plumb-bob

			String line
			The string line of a plumb-bob will commonly be made from one of the following: Cotton Nylon Polyethylene

			Cotton Cotton thread, when twisted or braided into string, is strong and flexible, though may snap or stretch if put under too much strain or if it is weakened by moisture, dryness or mildew.

			Nylon Nylon cord is very strong and flexible. It will not easily stretch and is resistant to mildew, dryness and heat. It is also rot-proof and waterproof.

			Polyethylene Polyethylene plastics are much more resilient to moisture and heat; they are waterproof, rot-proof and stronger than cotton lines of the same thickness.

			Twisted and braided lines Braided line is where the individual threads have been woven together in an interlocking braided pattern to increase its strength. Twisted line is type of yarn (woven fibres) and consists of interlocking threads that have been spun together to form a string or rope, increasing its strength.

			Which material should you choose?
			A braided nylon or polyethylene line is generally considered to be the best line for a plumb-bob. These types of lines are not easily stretched and they are water-proof, rot-proof, and resistant to mildew. As well as this, braided lines are typically stronger and tend not to spin like twisted lines do. This is important when trying to take accurate measurements with your plumb-bob.