Chalk line

It is an important tool in carpentry, and 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.

Use

A chalk line creates straight lines by the action of a taut string that has been previously coated with a loose, powdered dye, usually chalk. The string is then laid across the surface to be marked and pulled tight. Next, the string is plucked or snapped sharply, causing it to strike the surface, which then transfers its chalk to the surface along the straight line where it struck.

Chalk lines are typically used to mark relatively flat surfaces. However, as long as the line is taut and the two ends of the chalk line are almost in the same plane, the chalk line will mark all points the string touches on or near that plane once snapped. The objects to be marked do not need to be continuous along the line. Chalk lines can also be used across irregular surfaces and holey surfaces, for example on an unfinished stud wall.

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 and plumb-bobs are often sold as a single tool.