Just like there are a variety of different types of drills, there are also many different drill bits from which to choose. Drilling holes in wood can be done with just about any type of drill bit, but drilling holes in metal requires special bits. Harder metals like stainless steel and iron require even more specialized drill bits that can withstand more friction and pressure.
High Speed Steel (HSS)
High Speed Steel (HSS) drill bits are used in drilling holes in softer metal like aluminum. HSS bits are often coated with Titanium Nitrade. This coating helps the drill bit to cut more smoothly through metal without getting stuck. HSS drill bits can cut just about any type of household metal. HSS drill bits, which are usually black in color, can withstand more heat than other metal bits. HHS drill bits are the least expensive of the metal drill bits because they are not as durable and need to be replaced sooner than cobalt or titanium bits.
Cobalt Drill Bits
Cobalt drill bits are also used in drilling holes in metal. Cobalt drill bits have a copper finish and they are generally more expensive than other metal bits. Cobalt bits are the best choice for drilling holes in stainless steel and harder metals because they are stronger than HSS bits. Cobalt drill bits also stay cooler than HSS bits, which makes them a better option for drilling hard metals. Drilling into hard metals can take longer than with softer metals, so a drill bit can become hot. A drill bit becomes weaker as it heats up, so keeping a Cobalt bit cool increases its strength.
Titanium Drill Bits
Titanium drill bits are also good for cutting harder metals like stainless steel and iron. Titanium bits often last three times longer than HSS bits. The shafts of titanium drill bits are also usually bigger than HSS bits. As a result, titanium bits have less chance of snapping or breaking. Metal drilling often requires more torque on the drill, which can put stress on the shaft of a bit. Because it is stronger than many other metals, titanium drill bits do not wear as quickly. Instead of sharpening them or having to replace them, titanium bits can be used longer.