Red Seal Tool and Die Maker Practice Exam

What material is primarily used to create gauge blocks?

1. Plastic

2. Wood

3. Precision ground metal

4. Glass

The correct answer is: Precision ground metal

Gauge blocks, also known as gage blocks or Jo blocks, are precision measuring tools used to establish lengths. The primary material used to manufacture these blocks is precision ground metal, typically hardened steel or carbide. This choice of material ensures that the gauge blocks possess exceptional dimensional stability, wear resistance, and durability, which are essential characteristics for maintaining accuracy in measurement over time. The precision grinding process applied to these metal blocks creates flat and parallel surfaces that allow for precise stacking, effectively creating various lengths as needed for calibration and measurement purposes. Metal blocks also have the ability to withstand environmental factors, such as humidity and temperature fluctuations, that could affect their dimensions, thereby providing reliable and consistent performance. In contrast, materials like plastic, wood, or glass do not meet the stringent requirements for precision and stability that gauge blocks must adhere to in professional settings. For instance, plastic can deform under stress, wood can expand or contract with humidity changes, and glass can break or chip easily, making them less suitable for such precise applications.