What feature is typically used to adjust the worktable on column-and-knee milling machines?

The feature commonly used to adjust the worktable on column-and-knee milling machines is an adjustable knee. This design allows the operator to raise or lower the knee, which directly affects the height of the worktable in relation to the milling cutter. This adjustability is crucial for accommodating various workpiece sizes and for achieving precise cutting depths.

The knee itself is a component that supports the worktable and can be moved vertically. This mechanism ensures that the cutter can engage the workpiece effectively, allowing for a wide range of milling operations. The ability to easily adjust the knee enhances both the versatility and effectiveness of the milling machine.

Other options, such as a hydraulic lift, a detachable base, and a fixed guide rail, do not play a role in the typical worktable adjustment on this type of milling machine and instead serve different functions or are characteristics of other types of machinery. The hydraulic lift is more commonly associated with other types of machines that require lifting heavy components, while a detachable base is not relevant to worktable adjustments, and fixed guide rails are used for guiding movement rather than adjusting table height.