Milling machines are complex power tools that can perform a number of functions. In order to shape work pieces as desired, a large number of parts must work together. There are more milling machine parts than there are for most other power tools. Some of the stock parts can even be replaced with custom parts to meet the needs of the worker.
There are two main milling machine parts: the head and the table, or bed. Simply put, the head contains the cutting or drilling tool and the bed is where the work piece is set. Both the head and the bed are made up of many more parts that allow workers to perform the specific kind of milling they need to do. The exact parts of each also vary depending on whether the mill is a vertical or horizontal mill.
A vertical mill head will be made of a motor which turns a cutting bit. The head is mounted on an arm that can rotate depending on the angle the worker needs to perform drilling or cutting. A quill whose height can be adjusted by a wheel that is also on the mill head holds the bit.
In contrast, a horizontal milling machine has a round blade set through an axle, called an arbor, on the machine’s head. The head of a horizontal milling machine is generally not movable. Adjustments to the cut of the horizontal mill are made by adjusting the bed.
The bed of a horizontal mill makes up for the lack of complexities of the milling machine parts of its head. From top to bottom, a vise holds the work piece steadily in place. The vise can then be moved on a track horizontally across the blade by a feeding handle. Below the track, another device allows the worker to move the work piece away from and closer to the machine, and below all of this is the knee, which controls vertical motion on the horizontal mill.
A vertical milling machine's bed contains all the same milling machine parts as a horizontal mill's bed. The main difference is the vertical machine tends to have a longer track. Some may also feature a protective shield made of clear plastic surrounding the front and sides of the work piece. This is to ensure that in the process of milling, the worker isn't accidentally struck by parts of the work piece that may break off during normal milling work.
As with any power tool, milling machines require all these parts to function together properly in order to safely work. The large number of milling machine parts increases the price of the milling machine. As the parts are both expensive to purchase and maintain, most milling machines are used only in professional environments, although a home-based shop can keep one if the owner is prepared to handle the costs. A well maintained machine can last a user many years without needing major parts replacements.