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What Are the Different Types of Metal Drill Bits?

David Bishop
David Bishop

Metal drill bits are available in a number of shapes and sizes. The design of the bits depends on both the desired size of the hole and the material into which it is being drilled. While most metal drill bits are made from some type of steel or steel alloy, some tasks may require harder bits made from composite materials such as tungsten carbide. Attempting to use a softer drill bit on a material that it is not designed for it can damage the drill and cause serious injury, so it is important for people to use bits only for their intended purposes.

Carbon steel bits are primarily used to drill holes in wood, but some of the higher carbon bits also can be used on metal. While these are generally the cheapest metal drill bits available, carbon bits lose their sharpness faster and can overheat when drilling into metal surfaces. Carbon bits are primarily useful for odd jobs around the house and woodworking tasks.

A drill with a Forstner bit.
A drill with a Forstner bit.

High-speed steel (HSS) bits are made from tougher steel alloys that have a higher tolerance for heat. These bits are used in manufacturing and other applications that require the bit to be in constant use. HSS bits also may be coated with another material to make them last longer or perform better in certain applications. When drilling through more resilient materials, it may be necessary to use a drill press to keep the bit at the correct angle and position.

Drill bits are available in many shapes and sizes.
Drill bits are available in many shapes and sizes.

Drilling into very hard materials, such as stainless steel, may require a cobalt steel alloy. While these bits are usually more expensive, they are specifically designed to deal with tougher materials and will usually hold their edge longer. Cobalt alloy bits are usually more brittle than other metal drill bits, so users will need to use caution to avoid damaging their tools and materials.

Drill bits can be made of steel, carbon steel and tungsten carbide.
Drill bits can be made of steel, carbon steel and tungsten carbide.

Composite materials such as tungsten carbide are used to make bits and drill bit tips for use when drilling into brick, concrete and other masonry materials. These bits can be included in sets along with masonry screws and anchors or sold separately by size. Carbide bits usually retain their sharpness longer than other bits and are often used for certain industrial applications. Tungsten carbide also is used to form the support stem for more exotic drilling tools that use polycrystalline diamond (PCD) as their cutting surface. These are typically very expensive bits used for precision industrial applications.

Discussion Comments


I am getting ready to start work on a DIY project where I am going to need to drill through some brick. The last time I was involved with something like that, it was with my father, and he started drilling into the brick and it cracked in half.

Surely it isn't normal for a brick to crack whenever you are drilling into it, right? He claims that he was using a masonry bit, but I have never really looked at them enough to know if they look any different from a normal drill bit.

Anyway, do you guys think it was something to do with the bit not being the right type, or was it maybe that the bricks were just weak and cracked on their own? I plan on going out and buying a new masonry bit to make sure I am using the right thing. Is there anything I should be looking for specifically? Finally, is there anything I can do for the bricks or something I can do while I am drilling that will stop them from possibly breaking.


Once a drill bit starts to get dull, is there any way to sharpen them, or is the best thing to do just replace them with a new set?

Also, is anyone here familiar with auger drill bits? I had to use one of those for a project I was making one time. It was actually a catapult my friend and I were building one summer. For part of it, we needed to hollow out a large hole for a dowel rod to fit through. The auger bit was perfect because it was able to pull out a lot of wood all at once instead of just turning it all into saw dust.

I have seen some auger bits, too, that have a wide diameter and have to fit into a hand crank. I don't really know what someone would use those for, but I guess they have some purpose.


@jcraig - It doesn't sound like this is what you are using, so it is what I would suggest. They actually make drill bits that are very long. I have one that is a little over a foot long and is 3/8 inches, which I am guessing is the right size for a cable line. That should be more than long enough to get from the outside to inside.

I got my bit when I was trying to replace a frayed telephone line. The way I got the phone line through was just by taking an unbent coat hanger and tying a piece of string to it, and then tying the string to the phone line. Then I just pulled everything through the hole, and it was pretty simple.


I am trying to run a new TV cable line though my house on a splitter, but the problem I am coming up with is that I don't have a drill bit that is long enough to get from the outside into the inside. I have drilled the outside hole where it needs to be, but I am not quite sure where the hole needs to be on the inside. I'm afraid if I do make a hole from the inside, it won't quite be in the right spot, and it will be nearly impossible to get the cable through. Does anyone have any suggestions how to approach this?

If I do get the two holes lined up, then does anyone have any ideas about the best way to get the cable line from the outside to the inside? I figure once I put it through the first hole it will be difficult to get through the second. How do the cable people do it when they are installing the original lines?

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    • A drill with a Forstner bit.
      By: Amy Walters
      A drill with a Forstner bit.
    • Drill bits are available in many shapes and sizes.
      By: gavran333
      Drill bits are available in many shapes and sizes.
    • Drill bits can be made of steel, carbon steel and tungsten carbide.
      By: sandrex
      Drill bits can be made of steel, carbon steel and tungsten carbide.
    • Similar to drill bits, reamers are used to widen an existing hole in metal into an exact diameter.
      By: hejnarphoto
      Similar to drill bits, reamers are used to widen an existing hole in metal into an exact diameter.