Gauge for Lathe Tool Alignment

The primary purpose is to determine which gauge is specifically used for aligning the lathe tool with the work. This alignment is critical for achieving accurate cuts and finishes.

Understanding the Options

• Straight edge: Primarily used to check the flatness or straightness of a surface. It does not help align a lathe tool relative to the workpiece center or axis.
• Centre gauge: This gauge is designed to help set the compound rest angle and align the tool bit precisely with the centerline of the workpiece. It is particularly essential when cutting threads to ensure the tool is perpendicular to the workpiece axis.
• Try square: Used to check or mark right angles (90 degrees). It is not suitable for the angular alignment required for lathe tools.
• Thread gauge: Used to measure the pitch or form of existing threads, not for aligning the cutting tool itself.

Conclusion on Tool Alignment

Based on the functions of the available tools:

• The Centre gauge is the correct instrument for ensuring the lathe tool is properly aligned with the workpiece, especially concerning the workpiece's centerline.