Difference Between End Mill and Drill Bit

An end mill is a custom milled tool that is used to create various types of shapes, including slots, pockets, and circles. A drill bit, on the other hand, is a tool that is used to create holes. While both tools are made of carbide, an end mill is typically stronger and more durable than a drill bit. End mills can also be used to create custom geometry, whereas drill bits are limited to creating cylindrical holes. 

End mills have a larger diameter than drill bits and are fluted like a drill bit, but they also have shoulders that cut at an angle. This allows them to mill custom shapes into the workpiece. Drill bits, on the other hand, are simply designed to create cylindrical holes. While end Mills can be used to drill holes, they are not as efficient as drill bits and will wear out more quickly. 

So, when deciding which tool to use, it is important to consider the intended purpose. If you need to create a hole, a drill bit will be the better choice. However, if you need to custom-mill a shape into the workpiece, an end mill will be the better choice.

Common Type of End Mills

1. End mills in different shapes

End mills are made from a variety of materials, including high-speed steel, carbide, and cobalt. They are available in a variety of shapes, including flat, ball, and chamfer. Each type of end mill has its own advantages and disadvantages.

Flat-end mills are the most common type of end mill. They are used for general-purpose machining and have a wide range of applications. Flat-end mills are good for general-purpose machining, but they cannot reach into tight spaces. 

Ball end mills have a rounded tip that is used to machine concave surfaces. 

Chamfer end mills have a beveled tip that is used to machine-angled surfaces.

2. End mills in different number of flutes

The number of flutes on an end mill affects the characteristics of the tool. A higher number of flutes will result in a finer finish but will take longer to produce. 

The number of flutes on an end mill can vary from 2 to 8, with 4 and 6 flute end mills being the most common. The primary difference between end mills with different numbers of flutes is the amount of chip clearance they provide. A 2-flute end mill will produce a narrower channel for chips to flow through than a 6-flute end mill, for example. This can be beneficial in some applications where a narrow channel is desired, such as when machining slots or pockets. 

The more flutes there are, the higher the cutting speed and accuracy. However, more flutes also mean that end mills are more fragile and require more frequent replacement, which can result in a faster cut and better overall finish. And a lower number of flutes will remove material faster but the finish will not be as fine. 

End mills with different numbers of flutes can be used for different purposes. A 2 flute end mill, for example, are well suited for custom milling applications where a high degree of precision is required. Four-flute end mills offer a good balance between cutting speed and durability while six-flute end mills are ideal for heavy duty custom milling applications. Ultimately, the best end mill for the job depends on the specific requirements of the application.

The number of flutes on an end mill can also affect its strength and rigidity. A 4 flute end mill, for example, is typically stronger and more rigid than a 2 flute end mill.

3. End mills in different materials

End mills are available in a variety of different materials, which can be selected based on the specific application. Some of the most common materials used for end mills include carbide, high-speed steel, and cobalt. 

Carbide end mills are made from a variety of different carbides, including tungsten carbide, Titanium Carbide, and Vanadium Carbide. They are extremely hard and wear-resistant, making them ideal for cutting through tough materials. However, they are also more brittle than other materials, so they can be susceptible to breakage if they are not used properly.

High speed steel end mills are made from a high carbon steel that is designed to withstand high speeds without breaking or deforming. They are commonly used for cutting through softer materials such as aluminum or brass. 

Cobalt end mills are made from a cobalt-based alloy and are designed to resist heat and wear. They are often used in high-speed machining applications where heat and wear resistance are important.

Main Difference Between End Mill and Drill Bit

The main difference between an end mill and a drill bit is their respective geometry. Drill bits are designed to create cylindrical holes, while end mills are used for milling or cutting away material from a workpiece. Both tools are made from high-speed steel or carbide for increased durability. End mills have flutes along their cutting edges that remove material as the end mill spins. The number of flutes can vary, but most end mills have at least two. This type of cutting action produces large amounts of chips, which need to be cleared away from the workpiece regularly. 

Drill bits, on the other hand, have a single spiral flute that cuts material as it rotates. The spiral flute allows for the quick and efficient removal of chips from the workpiece. Drill bits are also available in a variety of sizes and lengths to accommodate different materials and applications.

Conclusion

End mills and drill bits are both used for cutting, but they have different purposes. An end mill is designed to cut across the grain of the material, while a drill bit is designed to cut along the grain. You can use an end mill to create slots and pockets in a piece of material, or you can use it to remove material from a surface.