High speed steel (HSS) is a form of tool steel; HSS bits are much more resistant to heat. They can be used to drill metal, hardwood, and most other materials at greater cutting speeds than carbon steel bits, and have largely replaced carbon steels in commercial applications.

A rotary cutting tool of cylindrical or conical shape used for enlarging and finishing to accurate dimensions holes that have been drilled, bored, or cored. A reamer cannot be used to originate a hole.

Cobalt steel is variations on high speed steel which contain more cobalt. Their main advantage is that they hold their hardness at much higher temperatures, so they are used to drill stainless steel and other hard materials. The main disadvantage of cobalt steels is that they are more brittle than standard HSS.