The scratch awl is basically a steel spike with its tip sharpened to a fine point. The tip of the spike is drawn across the timber, leaving a shallow groove. It may also be used to mark a point by pressing the tip into the timber. It is generally used when dimensioning and for laying out with the grain. It may also be used across the grain. However, a marking knife is preferred for this operation.
Scratch awls are traditionally used in leather-crafting to trace patterns onto leather. They are sometimes used in the automotive and sheet metal trades to punch holes and scribe lines in sheet metal.