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End mills are a type of cutting tool used on milling cutters, some of the most commonly used machine tools in machining. To an untrained eye, they closely resemble drill bits; however, unlike drill bits, which can only cut axially, end mills can cut in many different directions depending on the machine.

In most cases, end mills are used to perform rotational cuts in horizontal directions (lateral cutting), though some of them can cut axially, similar to drill bits. They’re most commonly used for slotting, profiling, contouring, counterboring, and reaming various materials.

In this article, we’ll explore various types of end mills alongside their applications in machining and parts manufacturing.

Importance of End Mills

End mills come in various shapes and sizes to suit a multitude of machining operations, such as profiling, slotting, drilling, and contouring. This, paired with their ability to cut through a wide range of materials, such as steel, aluminum, plastics, wood, and alloys, makes end mills exceptionally versatile.

In addition, they allow for extremely precise cuts and shaping when used in precise machining applications, which helps maintain part integrity, especially when machining more intricate and complex parts. Their versatility, precision, and material compatibility make end mills an indispensable part of every machinist cutting tool arsenal.

Different Types of End Mills

The varying shapes and sizes of end mills directly affects their application.

Ball Nose End Mill

Ball nose end mills, also known as ball end mills, have rounded tips, which makes them perfect for shaping delicately contoured surfaces. They’re also great for groove rounding, shallow slotting, pocketing, and various other contouring operations, such as corner rounding.

Square End

Square-end mills, also known as flat-end mills, are a general-purpose type of end mill, as they’re incredibly versatile and suitable for a wider range of applications, such as slotting, side and face milling, plunging, and profiling. Due to their design, these can deliver perfect 90° corner cuts and can even be suitable for abrasion and finishing applications.

Router/Fishtail End Mill

Router end mills typically have a cutting face that’s much thinner than the shank, which makes them perfect for cutting directly into the material due to the small cutting surface and the helical flute shape, which allows efficient chip extraction. They’re great for pocketing, routing, and contouring.

Bull Nose

Bull nose or corner radius end mills are very similar to square ends. However, with their unique design, instead of producing 90° corners in the workpiece, bull nose end mills produce a flat-bottomed groove with rounded corners, which is great for mold milling operations.

Roughing End Mills

As their name suggests, roughing end mills are mostly used for “roughing” stages, in which you roughly cut a basic shape. Roughing end mills make quick, rough shapes, which are then cut more precisely using finer cutters.

V-Bits

V-bit end mills are used for carving V-shaped grooves in the material and usually come in either a 60° or 90° variety. The sharp tips are used for cutting narrower paths, the curing sides are great for chamfering, and the wider bottoms are great for larger cuts.

Thread Mills

Thread mills are most typically used for creating threads in a workpiece using CNC machining. Their main advantage is that they gradually remove the material during threading, which is less stressful on the tool and the machine.

Solid Carbide End Mills

Carbide end mills are high-performance cutters, which have exceptionally hard cutting edges and great heat resistance, thus allowing for faster cutting compared to other end mills. These are great for a wide variety of materials, including cast iron, stainless steel, high-temp alloys, and titanium.

High-Speed Steel

High-speed steel (HSS) mills are more affordable than carbide mills. They’re the go-to cutters for more standard operations across a variety of different materials and generally offer good wear resistance. However, they’re not as heat resistant as carbide, resulting in more restrictions on feed rates and performance over time.

How to Choose the Right End Mill

Choosing the right end mill is crucial for successful and efficient machining, and what’s right for your specific application depends on several different factors, such as the type of material being cut, end mill coating, type, helix angle, number of flutes, and workpiece complexity.

If you want to learn more about end mills, don’t hesitate to contact our team or check out our wide assortment of tools, tool accessories, parts, and machine components.