Intro to Millwright Practice Exam

What type of drill bit has a spring-loaded centering pin?

1. Twist Drill Bit

2. Step Drill Bit

3. Hougen Rotabroach

4. Masonry Drill Bit

The correct answer is: Hougen Rotabroach

The correct answer is the Hougen Rotabroach. This type of drill bit is specifically designed for producing holes in metal through a process known as annular cutting. One of its distinctive features is the spring-loaded centering pin that helps to accurately position the bit on the workpiece before drilling. This ensures that the hole is started precisely where it is needed, enhancing the accuracy of the cut and minimizing the chances of the bit walking or slipping as it initiates the drilling process. In contrast, other types of drill bits, such as twist drill bits, step drill bits, and masonry drill bits, do not typically incorporate a centering pin. Twist drill bits are used for general-purpose drilling and rely on a pointed tip to create an initial hole, whereas step drill bits, designed for drilling larger diameters in thin materials, increase in diameter in steps without needing a centering mechanism. Masonry drill bits, on the other hand, are specialized for drilling into brick, stone, or concrete, and they feature a different design suited for harder materials, lacking any sort of centering pin functionality. Thus, the unique design and mechanism of the Hougen Rotabroach distinguishes it as the correct answer for this question.