ColumnThe tall main body. The knee slides up and down its front, and the turret sits on its top.
TurretThe round mount on top of the column. It lets the ram and head swing round.
RamThe arm on the turret that slides forward and back. It carries the head. Also called the overarm or top slide.
HeadThe vertical head on the ram's end, holding the spindle and quill. It can be tilted for angled cuts.
QuillThe sleeve round the spindle that slides down to lower the cutter. It works like a drill press's.
SpindleThe turning shaft that holds the milling cutter in a collet.
Milling cutterThe rotating cutting tool with teeth on its sides and end.
TableThe table the work is clamped to. It moves left and right under the cutter.
SaddleThe slide under the table. It moves in and out on the knee, for the cross feed.
KneeThe heavy casting that slides up and down the column. It carries the saddle and table.
HandwheelsHand-turned wheels and cranks that move the table, saddle and knee.
How this list was compiled: Read 2026-09-27. (1) US Army, TC 9-524, Fundamentals of Machine Tools (1996), chapter 8 and figure 8-1, https://archive.org/details/tc-9-524-fundamentals-of-machine-tools-1996 : the knee-type milling machine, its worktable resting on a saddle supported by a knee that rides up and down the column; the saddle moving in and out for cross feed; the turret and swivel head; the ram; the vertical head, quill and spindle; the table handwheel, crossfeed handle and vertical feed crank; the drive motor; the milling cutter. (2) Wikipedia, Milling (machining), https://en.wikipedia.org/wiki/Milling_(machining) , and its figure of a vertical milling machine: milling cutter, spindle, top slide or overarm, column, table, Y-axis slide, knee and base; the turret mill's quill; the ram-type mill's head on a sliding ram; handwheels; motors; cutters held in a collet in the spindle. Licence: own work
The drawing: Drawn for this site by script, 2026-09-27. Own work, nothing traced. Licence: own work
How it works
These are the parts of a milling machine, the vertical knee-type mill found in most school and hobby workshops, seen from the side with the front to the right.
Read the full guide
The cutting end
The turret on top of the column carries the ram, which slides forward to set the head over the work. A motor on the head turns the spindle, which holds the milling cutter, and the quill lowers them into the work.
Moving the work
The work is clamped to the table, which moves left and right. The table sits on the saddle, which moves in and out, and the saddle on the knee, which slides up and down the column. Each moves by a handwheel.
Table, saddle, knee: left and right, in and out, up and down. That is how the work moves under the cutter.
Questions and answers
What is the knee on a milling machine?
The heavy casting that slides up and down the front of the column, carrying the saddle and the table. Raising it brings the work up to the cutter.
What is the difference between a vertical and a horizontal mill?
In a vertical mill the spindle and cutter point down at the work. In a horizontal mill the spindle lies flat, and the cutters sit on an arbor held by the overarm.
What does the ram do?
It carries the head and slides forward and back on the turret, so the cutter can reach different parts of the table.