A knee milling machine is a sort of vertical mill. It has a horizontal X-axis that travels together with the vertical Y-axis. The worktable travels along the machining axis rather than is fixed. The knee mill's spinning head performs all Y-axis cutting operations. 
A knee mill machine is versatile equipment that may be used for various processes and workpiece types. It has a vertically adjustable work table that rests on a knee-supported saddle.
The knee is a machine casting that is both supportive and massive. By lying vertically on the column, the knee maintains the stability of a knee milling machine. It also keeps the column securely and firmly in place. As a result, the milling head and spindle remain vertically fixed throughout operations.

What Is The Basic Meaning Of The Term "Knee Mill"?

The term is derived from the manner the equipment operates. The knee mill was invented in 1936 by Rudolph Bannow's business, who built a knee-and-column vertical mill with a rotating turret and sliding-ram head.

Why Is It So Popular Today?

The knee milling machine is one of the most often used machine tools in machine shops worldwide. Machinists like the machine's open design, allowing rapid setups for essential work. 
Simply feed a workpiece into the mill, drill a few holes or tap something, and the component is finished. Its tiltable head, moveable ram, and turret also make it exceptionally adaptable in terms of its work envelope. The machine is adaptable and enables a variable work envelope.

Utilization Simplicity

Anyone with the proper training can operate a manual mill quite efficiently. It is often the most excellent place to start for newbies to the machining sector. You do not need to create code or configure sophisticated tooling applications.
It just requires a drill or endmill and a collet to get started. This is why the knee mill is a popular machine tool among machinists and metalworking enthusiasts all over the globe.

Flexible And Accurate

When performing angle cuts on the horizontal plane, the adjustment of the head allows for more accuracy. Knee milling machines are one of the most common production equipment because of their flexibility and stability.

What Are The Different Features Of A Milling Machine?

Column and Base, Knee, Saddle and Swivel Table, Power Feed Mechanism, Table, Spindle, Over Arm/ Overhanging Arm, Arbor Support, and Ram are milling machine elements. See below for a list of milling machine components and functions.

• Column And Base: The column and base of a milling machine support the other sections of the machine. An oil reservoir and pump are located in the column to lubricate the spindle. The column is supported by the base and includes a coolant reservoir and a pump to deliver coolant during milling operations.

• Saddle And Swivel Table: The saddle is on the knee, which supports the table. The saddle moves on a horizontal joint on the knee, and the dovetail is parallel to the spindle axis (in horizontal milling m/c). A swivel table is mounted to a saddle that swivels (revolves) in both directions horizontally.

• Knee: The gearing mechanism is contained inside the knee. Dovetail ways join the knee to the column. A vertical positioning screw often called an elevating screw, supports and adjusts it. The elevating screw is used to adjust the knee up and down by raising and lowering the lever with a hand or power feed.

• Power Feed Mechanism: The power feed mechanism is found in the knee. The power feed mechanism is used to regulate longitudinal (left and right), transverse (in and out), and vertical (up and down) feeds. The feed selection lever on the machine is positioned to indicate the desired rate of feed on the feed selection plates.

Feed is acquired on various universal knee and column milling machines by rotating the speed selection handle until the necessary rate of feed appears on the feed dial. Almost every milling machine has a quick traverse lever employed when a temporary increase in the speed of the longitudinal, transverse, or vertical feeds is necessary. 

• Table: A table is a rectangular casting shown on top of a saddle. The table is used to support the work or to hold work-holding gadgets. There are several T-slots for storing work and work-holding devices. 

It may be operated manually or with electricity. It engages and rotates the longitudinal hand crank to move the table by hand. It contacts the longitudinal direction feeding control lever to move it by power.’

• Spindle: The spindle of a milling machine is used to hold and drive the cutting tools. It is supported by the column and is placed on bearings. An electric motor drives the spindle using gear trains located on the column. 

The spindle face, which is close to the table, has an internal taper machined. Two keys on the front face offer positive driving for the cutter holder or arbor.

• Arbor Support: An arbor support is a casting with a bearing that supports the outer edge of the arbor. It also helps in aligning the arbor's outer end with the spindle. Arbor support prevents the outside edge of the arbor from springing during cutting operations. 

Arbor supports in milling machines are generally classified into two categories. The first features a tiny bearing hole with a maximum diameter of 1 inch. The second features a big bearing hole with a diameter of up to 23/4 inches.

• Ram: A vertical milling machine's ram is an overhanging arm. The milling head is connected to one end of the ram, which is positioned on the top of the column.

• Overhanging Arm: An overarm is a horizontal beam on the top face of a column. A single casting might slide in the dovetail manner on the column's top face.

• Accessories: Vertical milling attachments, swivel attachments, high-speed milling attachments, slotting attachments, universal division heads (indexing heads), circular milling attachments, rack milling attachments, vices, and arbors are standard milling machine accessories.

Conclusion

When it comes to cutting bigger things, the knee mill may be really useful. In short, a knee mill, like other milling machines, can conduct an extensive range of cutting and reshaping procedures.