Millwright Level 1 Practice Exam

What is the included point angle of a general-purpose drill bit designed for drilling most metals?

1. 90 degrees

2. 118 degrees

3. 150 degrees

4. 180 degrees

The correct answer is: 118 degrees

The included point angle of a general-purpose drill bit designed for drilling most metals is typically 118 degrees. This angle strikes a balance between cutting efficiency and strength, allowing the drill bit to penetrate metal materials effectively. The 118-degree angle provides a sharp point that helps to initiate the cut and aids in chip removal, reducing the chance of overheating and damaging both the tool and the workpiece. In contrast, a 90-degree point angle is commonly used for specific applications like countersinking, where a focused point is needed rather than cutting through materials. An included angle of 150 degrees may reduce the cutting aggression and is typically used for softer materials, which would not be ideal for most metal applications. Lastly, a 180-degree angle indicates a flat point and is generally unsuitable for drilling, as it offers no cutting action and is rarely employed in general-purpose drilling tasks. Thus, the angle of 118 degrees is the most effective for general metal drilling, contributing to the overall performance and efficiency of the drill bit.