The various types of milling cutters

End milling

End mills (middle row in the image) are tools with cutting teeth on both ends and sides. End mills are generally used to refer to flat-bottomed cutters, but they also include rounded cutters (also known as ball-nosed) and radiused cutters (also known as bull noses or torus). They typically have one or more flutes and are made of high-speed steel or cemented carbide. They are the most frequently used tool in a vertical mill.

End mill for roughing

Roughing end mills remove a substantial quantity of material quickly. This end mill has a wavy tooth shape cut on the periphery. These wavy teeth act as many successive cutting edges, resulting in a large number of little chips. This produces a relatively rough surface finish, but the swarf is in the shape of short, thin pieces, which are easier to manage than a broader, more ribbon-like portion, resulting in smaller chips that are easier to clean. Multiple teeth make simultaneous contact with the workpiece during cutting, decreasing chatter and vibration. Hogging is a term used to describe the rapid removal of stock with heavy milling cutters. Roughing end mills are sometimes referred to as "ripped" or "ripper" cutters.

The ball cutter

Ball-nose cutters or ball-end mills (bottom row in image) are similar to slot drills but have hemispherical cutter ends. They are ideal for 3-dimensional contoured shape machining in machining centers, such as molds and dies. In shop lingo, they are sometimes referred to as ball mills, even though the name has a different connotation. They are also used to alleviate stress concentrations by adding a radius between perpendicular sides.

A bull nose cutter mills a slot with a corner radius that is between that of an end mill and that of a ball cutter; for example, a 20 mm diameter cutter with a 2 mm radius corner. The silhouette is essentially a rectangle with truncated corners (either via chamfer or radius).

Slab mill for high-speed steel

Slab mills are used to quickly machine big, broad surfaces on manual horizontal or universal milling machines, either alone or in gang milling operations. They have been supplanted by the use of cemented carbide-tipped face mills in vertical mills or machining centers.

Face-and-side cutter

The side-and-face cutter has cutting teeth on both its sides and its perimeter. Depending on their use, they come in a variety of diameters and widths. The side teeth allow the cutter to produce unbalanced cuts (cutting on one side only) without deflecting the cutter, as a slitting saw or slot cutter (no side teeth) would.

This type of milling cutter was the first to be produced. They were the most prevalent type of milling cutter from the 1810s through at least the 1880s, but end mills now likely hold that distinction. HSS side and face cutters have traditionally been used to mill slots and grooves.

Gear cutter involute

There are eight cutters (excluding the rare half sizes) that will cut gears ranging from 12 teeth to a rack (infinite diameter).

Hob

These cutters are a sort of form tool that is used to produce gears in hobbing machines. Once configured under suitable conditions (blank size), a cross-section of the cutter's tooth will generate the needed form on the workpiece. A hobbing machine is a type of milling machine that has been modified.

Milling thread

A thread milling cutter works much like an endmill, circumnavigating the work in a helical pattern, as opposed to a hob, which engages the work much like a mating gear would (and cuts the blank gradually until it reaches the desired shape). Click here for Wheels For Shaped Machine.