What Type of Drill Bit Can Cut Through Metal?

Drill Bit Materials

• Manufacturers produce drill bits from several types of metal alloy, according to the application of the tool. In general, manufacturers clearly print both the bit's metal type and recommended applications on the product packaging. In order of relative strength, the most common types of steel alloy drill bits are high carbon, high speed and cobalt. Additionally, manufacturers often coat metal drill bit tips and shanks with carbide or diamond to increase strength. Notably, many of the stronger types of bits are more expensive and more brittle than standard bits.

Twist Drill

• Recognizable by the sharpened channels that coil around its shank, the twist bit is one of the most common types of metal drill bits. Unlike the woodworker's brad point bit, the metal-cutting twist bit's tip tapers to a conical point. Twist bits range in diameter from less than 1/32 inch to several inches. Standard twist bits may be 2 inches to 6 inches long, depending upon diameter, while specially designed drill bits, called aircraft drill bits, often exceed 12 inches in length.

Step Drill

• A single step drill bit, also called an adjustable drill bit, can create holes of several different diameters. The profile view of the step drill looks like a stacked set of discs arranged into a roughly conical form. The largest of the step drill's discs rests nearest the drill's base and the smallest at the drill's tip. Each disc cuts a hole of precise diameter and, by limiting or extending the depth of the drill's cut, a worker can adjust the hole's diameter.

Hole Saw

• Despite a name that suggests sawing, the hole saw bores through materials with a rotary drilling action. Used to drill a variety of materials, including all types of metal, the hole saw's large body resembles a hollow cylinder. Sharp teeth or mineral grit line the cutting edge of the hole saw's body, which creates large-diameter holes, usually through thin materials such as sheet metal.