A drill bit is a handy tool and has every part with great functionality.
It is imperative to understand all the primary functions of a drill bit, or else you may end up wasting your time and energy.
Once you are OK with different parts’ functionality, you will buy the best drill bit for your project.
You can see a video guide at the end also. I hope once you go through all this, then you will have pretty much clarity about drill bits parts and functions.
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Common Drill Bit Parts
See the below diagram, and you can see the name of different parts of a standard twist drill bit.
Different Parts of a Drill Bit are;
- Cutting Tip
- Body Clearance
- Chisel Edge or Dead Center
- Clearance Diameter
- Taper length
- Lip Angle
- Lip Relief Angle
- Lip length
- Helix Angle
- Chisel Edge Angle
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I will explain all these parts one by one. You can also see a video explaining all these in quite an easy way.
There are three main parts of any drill bit.
Point is the main part of a drill bit. It is the one that initiates the hole. The types of points are Brad, Plexi, taper, Split, Screw, etc. A cone-shaped surface formed at the end of the flutes which contains dead center, lips, and flanks, etc. is known as a point.
The point consists of the following major parts;
Dea Center, Lips & Heel.
Shank is the end part that is about to fix in the drill machine chuck. A shank can be straight or tapered. A tapered shank is a self-holding that can fit directly into the drill press spindle. Taper shank is also known as Tang. Part of the drill between neck and tang is known as Shank.
It is perhaps the longest part of any drill bit. It starts from cutting edge up to the neck of a drill bit. It contains many sub-parts like margin, web, helix angle, lips, flutes, land, chisel edges, etc.
The web is the central part of the body that joins the lands.
It is a small step between Shank & the body. Its diameter is a bit less than that of the shank. It has no significant value but only helps if the body needs to be coated and isolates the body & shank parts.
Plain twisted parts of the drill bit are the flutes. It is a significant part of dealing with the chips during the process. The flutes design is one of the factors to consider while defining the high-speed and low-speed drill bits.
It does the cutting through. It defines the quality of a drill bit. Different types of drill bits have different materials on the tip, like Diamond or Steel tips.
The highest part of the flutes. I recommend watching the video to understand correctly. It cannot be clarified in words.
This part aims to reduce friction between the wall and the ‘Hole (that is a reduced body). It also reduces heat as it can absorb it easily.
Chisel Edge or Dead Center
This part is the first to go through the drilling material. A chisel edge or dead center is the edge of the cutting blade. This is used when going to cut hard surfaces like stone, metals by hand. Edge formed at the extreme tip due to the intersection of flanks is known as Chisel Edge.
Reduction in the drill bit body to lessen friction during hole making & this diameter is called clearance diameter.
The margin is the strip that extends from the back at the length of the flutes. This is also the Full diameter of a drill bit.
The second part of the split shank is the Tang. It can be flat, tapered as per the requirements.
Taper Shank + Tang is called taper length.
This is the extreme extended length that goes through the surface area.
This is the outermost edge of the chisel.
This is the angle between the chisel edge and the out edge of the lip. Lip is the main cutting part of the drill bit.
Lip Relief Angle
The relief angle at the outer corner of the lip.
The center of the chisel, distant from the center, is called lip length.
This is the angle formed by two sides at the tapering point. For standard but it is 118°. But for hard and tougher materials to drill, it can go up 130°.
For Jabber, this angle is 118°, and for Stubb, it is more like 135°. This is best for hardened steel.
This is the angle between the in a side view of a twisted drill. It is also the angle of flutes about the job surface.
Commonly it is 30º. This 30-degree helix angle is also known as a standard helix angle.
Chisel Edge Angle
It is an angle between the chisel edge and the cutting lips—an indication of lip clearance.
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Video Guide | Drill Parts Visualised
This video has explained it amazingly…
What are the grooves in a drill bit called?
These spiral grooves are called ‘Flutes.’
What are split point drill bits?
The split point is an innovative geometry of drill bit tip that reduces ‘walking’ and starts the drilling quicker than other Standard Point drill bits.
This split point geometry also helps lift away the chipping, reducing the friction and increasing the drilling operation speed.
How do you read a drill bit size?
Usually, the size of a drill bit is punched at the shank—for example, ¼ inch, ½ inch, etc.
What is the drill angle?
The most common twist drill bit (sold in general hardware stores) has a point angle of 118 degrees, acceptable for wood, metal, plastic, and most other materials. However, it does not perform as well as using the optimum angle for each material.
What are the angles in a twist drill?
The helix angle is 32°. The tapering point angle may be 118° or 135°. The other customized drill bits may have any desired angle, but these two are the most commonly used and treated as standard.
Why is a drill bit angle of 118° & 135°?
This 118° point angle is normally used for soft materials like wood, while 135° is used for hard materials like stainless steel.
What are the main parts of a drill bit?
The main parts of drill bits are Body, Shank, and Point.
What material is used in the drill bit?
The base material is steel, and other forms are
- Plain Carbon Steel –
- High-Speed Steel – HSS
- Cobalt Steel
- Tool Steel with Carbide Tip
What are drill bit tip styles?
There are different styles available the mainly used are;
- Taper Point
- Conventional Drill Point
- Split Drill Point
- Brad Point
- Fishtail Point
What is the purpose of Flute and styles?
The main purpose of the flute is to eliminate the chipping so that reduction in friction. Types include
- High Helix or Fast Spiral
- Low Helix or Slow Helix
What is the purpose of Shank and styles?
Shank is the one that is going into the chuck of the drill machine. It can be straight, tapered, screwed, etc.
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4 thoughts on “Twist Drill Bit Parts and Functions”
Most cases we can’t figure out major functions of drill bits. If you want to buy the best drill bits you have to know the functions mentioned above. I think most important parts of drill bits are it’s body and shank. Very informative article.
Thank you, for your nice appreciation comment. Larry Anderson
I can say the tip angle is equally important if you are going for precise jobs (Metals, Porcelain layer, etc.) like Body & shank part as you said.
Excellent guide with easy to read diagrams. Fantastic ‘customer service’. Thanks for helping people to make informed choices.
Thank You, Andy. Stay Safe & blessed