Millwright Level 1 Practice Exam

Which grade of surface plate is commonly used in a shop setting?

1. Grade A

2. Grade B

3. Grade C

4. Grade D

The correct answer is: Grade B

In a shop setting, Grade B surface plates are commonly used due to their balance between accuracy and cost-effectiveness. Grade B plates are manufactured to a tolerance that is suitable for general machining and layout work, making them ideal for many practical applications in a typical millwright environment. They provide a good level of flatness, enabling machinists and millwrights to perform setups, inspections, and layout work accurately, which is crucial for achieving precise machining results. While Grade A plates offer higher precision and are more suitable for high-stakes inspection or critical machining tasks, their cost and the level of maintenance required can be prohibitive for everyday shop use. Grades C and D are often utilized for less critical tasks and may not provide the required accuracy or durability for regular use in a shop setting. Thus, Grade B is seen as the optimum choice for combining adequate precision with the practicality needed in a busy workshop.