ASVAB (Armed Services Vocational Aptitude Battery)Auto and Shop Information (AS)Easy
A homeowner is selecting a drill bit for boring a precisely sized hole in a piece of metal. Which type of drill bit is specifically designed for high precision and clean holes in metal, often requiring a pilot hole first?
- AAuger bit
- BTwist bit
- CSpade bit
- DBrad-point bit
Show answer & explanationAnswer & explanation
Correct answer: B. Twist bit
Twist bits, also known as jobber bits, are the most common type of drill bit for general use and are well-suited for drilling in metal, wood, and plastic. They come in various materials (HSS, cobalt) for different metal hardnesses and are designed for precision.
Why the other options are wrong
- A. Auger bits are designed for deep, clean holes in wood, often used in woodworking or timber framing.
- C. Spade bits are primarily used for drilling large, rough holes in wood, not precision in metal.
- D. Brad-point bits are designed for clean, splinter-free holes in wood, featuring a sharp tip for accurate starting.
Twist Drill Bit
A common drill bit type with helical flutes, used for general-purpose drilling in various materials including metal, wood, and plastic.
- Most versatile and widely used drill bit.
- Comes in different materials (HSS, Cobalt, Carbide).
- Requires lubrication and slower speeds for metal.
Memory trick: Each bit has its job, a twist for metal's tough knob.