What End Mills are and How They Work

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What is an End Mill?
End mills are a cutting tool usually used industrial milling processes. Sometimes they can be confused with drill bits but a drill bit can only cut in the direction of the piece whereas an end mill bit can cut in all directions. Profile milling, face milling, tracer milling and plunging are some of the applications end mills are used for. However, before understanding a little more about end mills, you should probably be brought up to speed as to what milling actually is, just in case you are not sure.

What is Milling?
Going back a little bit… Milling is the process used to remove to remove material from something using rotary cutters. The term is Bradly used to talk about different machines and equipment and processes. Milling can be used on individual parts as well as heavy duty operations. Most commonly it is used for machining parts to make them a certain size or shape. Many different kinds of machine tools are used for milling and end mills are only one part.

Types of End Mills
There are a lot of different types of end mills that a variety of machines use, such as the Swiss CNC and others that are in machine shops. Here are just a couple to give you an idea of the functions.

Flute End Mills
This type of mill allows for spiral cutting and slotting. If a few flutes are used it once this can reduce chip load and make the finish better.

Carbide End Mills
Carbide end mills increase the sturdiness while being able to operate at high speeds. A carbide insert is usually used in shops that use newer machines that are more rigid in order to protect the tool.

Cobalt End Mills
This is very similar to the carbide end mills in that it can operate at high speed. However, the difference is that this material is abrasion resistant unlike the standard high speed steel tools.


HSS stands for “high speed steel” and is how a majority of end mills are made. This material is usually fairly cheap but you get what you pay for because HSS is not as high quality as cobalt or carbide end mills.

This end mill has an odd shape because it is made to move remove a lot of material in a short amount of time. Generally speaking, the rougher can remove material almost three times faster than a traditional end mill.

These are just five of many types of end mills that are available including single end, stub length, drill point, high helix, corner rounders and more.

How are End Mills Used?

There are several different functions for end mills depending on the project in the process. Being successful in end milling depends on how well the tool is supported. Here are the few basic procedures of the end mill:

Face milling – this is for small areas and produce scratched look for the finish.

Keyway production ? this is when two end mills have to produce quality key way.

Woodruff keyways ? this is usually done with a single cutter during a straight plunge.

Specialty cutting – this includes tapered surfaces milling, dovetails and more.

Finish profiling ? this means to finish the exterior part of the shape.

Cavities Die Work ? usually this involves plunging and pocket cutting and producing 3-D shapes.

There is only so much that can be covered in one article. End mills can be a complex subject and figuring out how to use them, as well as when to use them and which one to use for what process, can take a lot of work, patience and training. Some end mills have several functions and are not only used for the one process or operation. Using the right end mill is important to having the correct result when you are finished. If you use the wrong end mill, the entire project could be ruined. Be careful is choosing and if you are unsure even a little bit, get a second opinion before testing something that you are unsure of. It can be unsafe as well as destroy your project.


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