Fig. 28 shows a marking gauge being used on a piece of timber. The timber has been selected for its working properties and appearance. Different types of ti...

(a) The three parts of the marking gauge are:

• A - Stem (beam): The long bar that extends from the stock. It slides through the stock to set the required distance from the datum edge. The stem carries the spur at its end and is typically made from a hardwood such as beech for its smooth grain and resistance to wear. [1]
• B - Stock (fence): The rectangular block that presses against the edge of the timber (the datum edge). It slides along the stem and is locked in position with a thumbscrew. Its flat face ensures accurate, consistent registration against the workpiece edge. [1]
• C - Spur (pin): The pointed metal pin at the end of the stem that scribes a fine line into the surface of the timber. It is sharpened to a point or chisel edge to cut cleanly into the wood fibres. [1]

(b) A marking gauge produces a scribed line at a consistent, fixed distance from the datum edge along the entire length of the workpiece. Unlike a ruler and pencil, which rely on the user to hold the ruler steady and draw freehand, the stock of the marking gauge maintains continuous contact with the datum edge, eliminating variation. The scribed line is also finer and more precise than a pencil line, which has variable thickness. Additionally, repeated identical lines can be marked on multiple pieces without re-measuring each time, improving speed and consistency in batch work. [1]