What Is a Bore Drill Bit?

K. Reynolds
K. Reynolds
Man with a drill
Man with a drill

A bore drill bit is a tool used for cutting cylindrical holes in a variety of materials such as wood, drywall and metal. It does this by rotating the bit attached to the drill to cut a hole into the surface of the material. This bit can drill holes in a wide range of sizes from a diameter of 1/4 inch (0.635 cm) to 6 inches (15.24 cm). It drills quickly and efficiently, even in hard wood or metal. The bit is usually attached or held by a drill which rotates the bore drill bit with enough torque and axial force to cut a hole into the material being drilled.

Two parts make up a bore drill bit — namely the shank, which is the part held by the drill, and the cutting edge, which enters the material being drilled. They normally come in different sizes which correspond to various sizes of holes they will drill. Most outlets selling drills will have a size chart to help the buyer determine the exact size to purchase.

The geometrical structure of a bore drill bit can further be described in numerous ways. The spiral of a drill bit refers to its rate of twist, which determines the rate at which it removes chips from the drilled material. There are fast spiral drills for drilling materials like wood and slow spiral drills for applications that require it, such as drilling aluminum.

The point angle of a drill refers to the angle at its tip. Generally, the point angle of a bore drill bit depends on the kind of material being drilled. For example, harder materials can best be drilled using a bit with a larger point angle while softer materials are drilled using bits with a sharper angle. The amount of force applied on the drill bit’s cutting edge is usually determined by the bit’s lip angle. A bigger lip angle ensures a more aggressive drilling.

Choosing a bore drill bit that is appropriate to the task can sometimes be confusing. The purchaser simply needs to understand the types of bore drill bits on the market, however. A few examples of these types include the twist drill bit, used to cut small holes in both wood and metal; the spade drill bit, used to cut holes of up to 1.5 inches (3.81 cm) in wood; and the expansion bore drill bit, for drilling wide 3 inch (7.62 cm) diameter holes in wood.

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Discussion Comments


Whenever you are using a bore bit to cut through metal, do you have to have some sort of lubrication to stop the metal from sparking or getting too hot?

I have seen TV shows where you get to see machines cutting out metal pieces, and those machines are always well lubricated, so I wondered if the same needed to be done at home when cutting metal.

Also, I have never seen any of the bits that are specially designed for metal, but are they the same shape as the ones used for wood? If you were using a spade bit, it seems like you would end up with a really rough edge using a spade bit. If it was sheet metal or something you were cutting through, it could even tear the surrounding metal.


Has anyone here ever seen or used a bore drill bit for masonry? They are really neat.

Instead of being the normal round bit you would use for wood, it is a long, hollow cylinder that is about six inches long. On the drilling end are a few teeth that are diamond coated to help cut through dense material. To stop the bit from getting jammed, the sides of the cylinder have a few holes cut in them.

I had never seen one until I was at my parents' house when they were having a new spigot added to their house. The person installing it used one to cut through the brick. I was surprised how easily it cut through the stuff. He said brick was one of the easiest materials to drill through, but the bit could even cut through marble countertops.

He also said because the bits are diamond coated they usually cost between 80 and 200 dollars depending on the size.


@ - I know the two different drill bits you're talking about. This article seems to be describing more of the second bit you are talking about, but I am with you. I have always called it a spade bit. The first bit you are talking about with the round shape I have always called a hole bit. That is just the name I came up with. I don't know if that's what it's really called.

A quick search of some pictures for a bore drill bit online shows the spade bit, so it looks like it can be called both things. Maybe it is just the case that a bore drill bit refers to more of a class of bits that make holes rather than a specific shape of drill bit.


I have used two different types of drill bits to make holes, but I'm not sure which one is really called a bore drill bit.

For anyone who has ever drilled the holes for a doorknob, you know the two I'm talking about. One of them is used for the main hole. It is round and takes out a whole round section of the wood. The other kind is used to make the hole for where the latch comes out of the side of the door. This bit is kind of a square shape with a pointed tip. Personally, I've always called these spade bits, but I'm thinking that might not be right.

Hopefully someone knows what I'm trying to describe.

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