A chalk line or chalk box is a tool for marking long, straight lines on relatively flat surfaces, much farther than is practical by hand or with a straightedge.
It is an important tool in construction and carpentry, the working of timber in a rough and unplaned state, as it does not require the timber to have a straight or squared edge formed onto it beforehand.
A chalk line draws straight lines by the action of a taut nylon or similar string. Specifically, the string (previously impregnated or coated with a loose dye such as chalk) is laid across the surface to be marked and pulled tight. The string is then plucked or snapped sharply to cause the string to strike the surface, transferring the chalk to the surface along that straight line. Chalk lines can also be used across surfaces with holes in them, for example on an unfinished stud wall. As long as the line is taut and the two ends of the chalk line are in the same plane, the chalk line will mark all points on that plane that it touches once snapped.
The primary problems associated with improper maintenance of a chalk line are string breakage due to excessive tension on the line, and degradation of the line associated with moisture contamination.
Chalk lines have been in use since ancient Egypt, and used continuously by builders in various cultures since.
In East Asia, an ink line is used in preference to a chalk line. This is a silken cord, stored on a combined reel and inkpot called a sumitsubo. Alongside the line reel is a cavity filled with ink-soaked cotton fibres, which the line is drawn through as it is unreeled. These sumitsubo are highly decorated and much-prized by their owners. As with many such tools, they're often made by their users while apprentices.
On the completion of a major building, such as a temple, a large celebration or topping-out ceremony is held. As part of this event, a set of symbolic carpenter's tools are freshly made and presented to the new building. A sumitsubo is a traditional tool included with them.
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- "(Fetched 2009-04-12)". Google.com. Retrieved 2012-12-28.
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- "Gallery of Sumitsubo".
- Toshio Odate. Japanese Woodworking Tools. ISBN 0-85442-075-4.
- Azby Brown. The Genius of Japanese Carpentry. Kodansha America. ISBN 0-87011-897-8.
|Wikimedia Commons has media related to Chalk lines.|
- Chalk line – One person operation (video)
- Chalk line – Two-person operation (video)
- Hand-made chalk-line (video)