MACHINING Copyright Goodheart-Willcox Co., Inc. Chapter 26 Milling Machines 469 Milling Flat Surfaces on a Vertical Milling Machine 1. Use a vise if the work cannot be clamped directly to the table. Clean the base and the worktable. Bolt the vise to the machine. 2. If extreme accuracy is required, align the milling machine spindle head and the worktable vise with a dial indicator. See Figure 26-70. 3. Wipe the jaws and the bottom of the vise clean with a shop rag or towel. Place the work on clean parallels in the vise. Tighten the jaws and tap the work onto the parallels with a mallet or soft-faced hammer. Use paper strips to check whether the work is on the parallels solidly. Protect the vise jaws with soft metal strips if the work is rough. 4. Select an appropriate cutting tool and toolholder. Mount the cutting tool into the toolholder if this has not already been done. SAFETY NOTE SAFETY NOTE cutter teeth with a thick cloth. 5. Mount the toolholder and cutting tool in the spindle of the mill. Make sure that both are clamped securely. 6. Adjust the machine to the proper cutting speed and feed. 7. Turn on the machine and check the cutter rotation and direction of power feed. If these are correct, loosen all worktable and knee locks, and position the work under the rotating cutter until it just touches the work surface. 8. Set the micrometer dial to 0. Back the work away from the rotating cutter and raise the table the required distance. 9. Tighten all locks (except longitudinal), turn on the coolant, and power-feed the work into the cutter. Do not stop the work during the machining operation. SAFETY NOTE SAFETY NOTE cut is in progress or while the cutter is rotating. 10. Complete the cut. Stop the cutter. Return the work to the starting position. Never feed the work back under the rotating cutter. 11. Following these directions, make the number of cuts necessary to bring the machined surface to size. 26.8.3 Squaring Stock The sequence for squaring stock on four sides on a ver- tical milling machine is the same as that described ear- lier in this chapter for a horizontal milling machine. If the piece is short enough, the ends may be machined by placing it in a vertical position, Figure 26-71A. Otherwise, it may be machined with an end mill as shown in Figure 26-71B. Goodheart-Willcox Publisher Figure 26-70. Using a dial indicator to align the spindle and vise on a vertical mill. Mount the dial indicator in the spindle chuck. Rotate the spindle and dial indictor by hand as shown to determine if the milling head is perpendicular to the worktable. Dial indicator Machine table Goodheart-Willcox Publisher Figure 26-71. Squaring the ends of a part. A—A short part can be aligned with a square, clamped solidly, and then machined. The movable jaw is not shown so the work and square can be viewed clearly. B—Parts can also be squared on the ends by clamping them into the vise in this manner. The vise jaw must be aligned at a right angle to the column for this method of squaring the end. A B Work Vise Vise Work Parallels