Graphical Construction Glossary >> General construction, Woodwork. >> Hand Tools >> Plumb Bob

Plumb Bob

A weight suspended on a string line, cord or wire to find true vertical. The main metal used for this was lead, from the Latin for lead Plumbum. Also called a plummet.

Plumb

Exactly vertical. If a member is vertical it is said to be "plumb". If not it is said to be "out of plumb".

String line.

A line usually out of string, but also used is wire, cord, nylon fishing line etc. When stretched tight it is used as an aid to creating straight lines.

Plumb Rule

A length of wood from which a plummet can be conveniently strung to find vertical.

Above is a two thousand years old Roman plumb-bob in the British Museum.

Alongside is sketch of a plumb rule.

The plummet needs a line that it is suspended from and it creates a true vertical reference line. It can also be used to find a point directly below the point that it is suspended from.
A string line on it's own is also a very useful tool. The shortest distance between two points is a straight line, so by stretching a line between two points we create something to measure off to straighten building members.

See here for more on using plummets and string lines.

• Go To Top : plumb bob
•  
• << BACK: eld box
• hand brace : NEXT >>

If you didn't find exactly what you are looking for try this search tool that will search the site and the web.

"What can be added to the happiness of a man who is in health, out of debt, and has a clear conscience?
Adam Smith 1723-1790

"When we build, let us think that we build for ever."John Ruskin 1819-1900