Used Vertical Milling Machines

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A vertical milling machine, along with an engine lathe, are the two most common machines found in all metalworking shops. The vertical mill can be used to drill or bore holes, cut key-ways or slots, carve out cavities, ream and tap holes, face mill parts and numerous other applications. The most common and versatile vertical mill found in almost all shops is the Bridgeport-type mill, or turret mill. This design incorporates a head mounted on the end of a ram that can be swiveled or rotated, so as to be positioned at any imaginable angle.

The upper part of the mill is designed for versatile positioning of the cutting tool. There are actually 5 position motions incorporated into just the head area of a turret type vertical mill. First, there is a ram mounted on top of a circular column that can be rotated 360 degrees (like a tank turret - hence the name turret mill). Then the ram can be slid forward or back. The head is mounted on a compound joint that can rotate side to side or tilt forward and back, then, finally, the quill can be moved in or out of the spindle.

The lower part of the mill is devoted to moving ...
... the work piece back and forth, up or down and side to side to bring the work piece into proper alignment against the cutting tool so as to actually do work on the part. The lower part of the machine consists of a table mounted to a saddle, which sits on a "knee" - the reason this mill is also sometimes called a knee mill. The knee is attached to the column and rides on ways that allow the knee to be moved up and down, bringing the table and work piece closer or further away from the spindle.

The table is a long rectangle with T-slots cut into it to permit hold-down clamps to be used to fasten a work piece or item of tooling (such as a vise or rotary table) securely to the table. This table is mounted onto a saddle that permits to axes of motion - left and right, and in and out. The saddle is mounted on the knee, which permits up and down motion.

A typical vertical mill is a manual machine. It is designed to be used by an operator turning handles and hand wheels. All operations typical of this machine type can be performed completely manually - only the spindle requires a motor to power the rotation of the cutting tool. But, over the years many options for alleviating the manual hand wheel turning have been developed in order to increase productivity and ease operator fatigue.

These options or accessories include power feeds for the table X and Y axes, power down-feed for the quill, and power elevation for the knee. In addition, power tool locking is a common option. Digital readouts for the table provide valuable assistance in positioning workpieces and, a readout on the quill can help determine depth of cut.

CNC packages for vertical mills are common today and can be applied to just the table - a 2 axis control, or to the table plus either the quill or knee for full 3 axis machining. These CNC packages most often permit hand machining as well, which makes the machine a most versatile machine to have, because it can be used for both production and for tool room applications.