Basic Construction and Classification
The milling machine has a power-driven spindle. An arbor for holding multitooth cutters fits into the spindle. The cutting edges or teeth on revolving circular cutters remove a controlled amount of metal at each revolution of the cutter. The workpiece is mounted on a movable table and is fed against the cutter. The table can be moved either by hand-feed or by power-feed. When several cutters are mounted on the arbor, several surfaces can be machined in one operation. The knee-and-column type of...
Lathe Centers
The live center is stationary in the main spindle of the headstock. It is called live because it turns with the workpiece. The dead center is placed in the tailstock spindle, and it does not rotate with the workpiece hence the term dead center . The live center does not have to be hardened because it rotates with the work. The dead center must be hardened because it does not rotate and must withstand the friction of the workpiece against it. Hardened centers are usually indicated by grooves cut...
Holding the Work
As shaper operations are concerned primarily with small work-pieces, the work is usually held in either a vise or a chuck. These holding devices are auxiliary to the table or machine. It is important to place the stops T-bolts properly. If the work were laid on the table without the stops to resist the thrust of the cutting tool on the cutting stroke, the cutting tool would push the work rather than cut it. Large pieces of work that cannot be held in a vise should be fastened to the table. In...
Stroke Adjustment
The ram should be adjusted to provide the proper length of stroke and to provide the proper position of travel over the workpiece. The stroke adjustment screw see Figure 15-2 can be turned to produce either a shorter or a longer stroke. A handle is provided on most machines for the square head of the adjusting screw. Unless the operator is familiar with the machine, trial and error can determine the direction of turning the stroke adjustment screw for either a longer or a shorter stroke. The...
Classification Txe
The types of dividing heads used on milling machines are plain, universal, and helical. Dividing heads can also be classified as to size for example, the Cincinnati Milacron Company dividing head is available in three different sizes . The basic parts of a plain dividing head are shown in Figure 13-2 and Figure 13-3. In a plain dividing head, the spindle rotates about a horizontal axis. The principal parts of the dividing head are spindle, worm wheel, worm, index plate, index pin, and sector....
Slotter Operations
Workpieces that are to be machined on the bottom side cannot be mounted directly on the table surface but should be mounted on parallel strips to give clearance for the cutting tool Figure 17-2 . The height A of the parallel should be a large enough distance to provide work clearance. Since workpieces that are to be machined on the bottom side cannot be mounted directly on the table surface Figure 17-2 Proper clearances for a cutting tool, work and table. Figure 17-2 Proper clearances for a...