Although there are a wide variety of techniques that are used to turn raw materials into finished parts for special jobs, a few of them are the most common. A typical custom machine shop, for example, will rely on lathing and milling for a large fraction of its output, with these two versatile approaches being capable of supplying much of the shaping that is typically necessary.

In fact, the two techniques are similar in a number of ways, while also differing in fundamental ones. Both make heavy use of rotation, with milling relying on cutting blades that circulate continuously. The approach known as lathing, on the other hand, has the item to be shaped doing the turning, as a spindle that it is mounted on keeps it spinning.

Although they are so similar in some ways, then, these two approaches are used to satisfy very different needs. Specialists at custom machining like AVSmachineandtool make use of lathing where entirely symmetrical output is desired, something that is actually quite common for many industrial uses. Pulleys of all kinds, for example, tend to require this kind of work, as do rollers, bearings, spindles, axles, and a whole range of other parts.

Milling, on the other hand, is used when the part in question will be of a basically different final sort. Instead of being restricted to turning out mostly symmetrical pieces, a milling machine that was properly set up by a precision machining can be used for virtually free-form work. Although there are many different kinds of milling equipment, they all allow some degree of freedom for the rotating cutting implement, and this results in a range of capabilities.

In some cases, for example, the corners of the implement will be used to mill recessed details into the face of a basically flat part. When a piece of sheet steel has been cut into a rough shape, a milling approach of this kind might allow the resulting part to fit closely against the features of another surface once it is installed.

For other applications, the cutting tool will be used to strip away even more material. A mill can be used, for example, to create pronounced, three-dimensional features like the teeth of a gear, something that would not be possible on a lathe. In fact, many projects involve first turning a part on a lathe to get it into approximately the right shape, after which a mill is used to do more detailed work.