A scratch awl is a woodworking

Woodworking

Woodworking is the process of building, making or carving something using wood.-History:Along with stone, mud, and animal parts, wood was one of the first materials worked by early humans. Microwear analysis of the Mousterian stone tools used by the Neanderthals show that many were used to work wood...

 layout and point-making tool. It is used to scribe a line to be followed by a hand saw

Hand saw

In woodworking and carpentry, hand saws, also known as "panel saws", "fish saws", are used to cut pieces of wood into different shapes. This is usually done in order to join the pieces together and create a wooden object. They usually operate by having a series of sharp points of some substance...

 or chisel

Chisel

A chisel is a tool with a characteristically shaped cutting edge of blade on its end, for carving or cutting a hard material such as wood, stone, or metal. The handle and blade of some types of chisel are made of metal or wood with a sharp edge in it.In use, the chisel is forced into the material...

 when making woodworking joints and other operations.

The scratch awl is basically a steel

Steel

Steel is an alloy that consists mostly of iron and has a carbon content between 0.2% and 2.1% by weight, depending on the grade. Carbon is the most common alloying material for iron, but various other alloying elements are used, such as manganese, chromium, vanadium, and tungsten...

 spike with its tip sharpened to a fine point. The tip of the spike is drawn across the timber, leaving a shallow groove

Groove (machining)

In manufacturing or mechanical engineering a groove is a long and narrow indentation built into a material, generally for the purpose of allowing another material or part to move within the groove and be guided by it. Examples include:...

. It may also be used to mark a point by pressing the tip into the timber.

This instrument is generally used when dimensioning and for laying out with the grain. It may also be used across the grain. However, a marking knife

Marking knife

A marking knife is a woodworking layout tool. It is used to scribe a line to be followed by a hand saw or chisel when making woodworking joints and other operations....

is preferred for this operation.