« Back to Dictionary Index

A twist drill is a common type of drill bit used for drilling holes in various materials such as metal, wood, and plastics.

Features of a Twist Drill:

  1. Spiral Flutes (Grooves):
  • A twist drill is characterized by its spiral-shaped flutes or grooves that run along the length of the drill bit. These flutes are designed to evacuate chips (metal shavings or debris) generated during the drilling process.
  1. Point Angle:
  • The tip of a twist drill typically has a specific point angle, which can vary depending on the intended application. Common point angles include 118 degrees for general-purpose drilling and 135 degrees for drilling harder materials.
  1. Cutting Edges:
  • Twist drills have cutting edges along the tip that initiate and maintain contact with the workpiece during drilling. These edges are sharpened to facilitate the cutting action and create the hole.
  1. Shank:
  • The shank of a twist drill is the non-cutting end that is inserted into the drill chuck or collet of a drilling machine. The shank may have different shapes and sizes to fit various types of drill chucks.
  1. Materials and Coatings:
  • Twist drills are typically made from high-speed steel (HSS), cobalt steel, or carbide for drilling different materials efficiently. Some drills also feature coatings such as titanium nitride (TiN) or cobalt for improved wear resistance and heat dissipation.

Functionality:

  • Chip Evacuation: The spiral flutes of a twist drill serve to channel the chips generated during drilling away from the cutting edges and up the flutes to the surface. This prevents clogging and overheating of the drill bit and workpiece.
  • Versatility: Twist drills are versatile tools used in various industries including metalworking, woodworking, construction, and manufacturing. They can drill holes of different diameters and depths depending on the size and type of the drill bit.
  • Precision and Efficiency: Proper use of twist drills ensures accurate hole placement and size, contributing to the overall quality and efficiency of drilling operations.

Applications:

  • Metalworking: Twist drills are extensively used in metalworking industries for drilling holes in metals such as steel, aluminum, brass, and stainless steel.
  • Woodworking: They are also employed in woodworking applications to drill holes in wood and composite materials.
  • Plastics and Composites: Twist drills with specialized designs are used for drilling holes in plastics and composite materials where chip control and material integrity are critical.

A twist drill is a versatile and essential tool for creating precise holes in a wide range of materials. Its spiral flutes facilitate efficient chip removal during drilling, ensuring smooth operation and extending the tool’s lifespan. Twist drills are available in various sizes and configurations to suit different drilling requirements across various industries and applications.

« Back to Dictionary Index