Knee-type milling machines employ a vertical workspace supported by a knee, which is an adjustable vertical casting. The knee supports a saddle and can be adjusted to allow for a customisable workspace.
A ram-type machine is used to allow the tooling to position itself on a greater range of space with regards to the workpiece. The ram-type machine has a spindle on a movable housing, which can move within a set horizontal plane. The universal ram-type milling machine includes a swivel housing that increases the range of cutting movements.