460 Modern Metalworking Copyright Goodheart-Willcox Co., Inc. Goodheart-Willcox Publisher Figure 26-41. Whenever the setup permits, cuts should be made toward the solid jaw of the vise. Cutter Cutt rotationon Solid jaw Direction of feed Goodheart-Willcox Publisher Figure 26-42. Aligning a vise jaw using a dial indicator helps ensure work accuracy. Milling Flat Surfaces on a Horizontal Milling Machine 1. Check and lubricate the machine. 2. 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. Place the vise as close to the column as the work shape will allow. When pos- sible, pivot the vise so the solid jaw supports the work against cutting pressure, Figure 26-41. 3. If extreme accuracy is required, align the vise with a dial indicator, Figure 26-42. Otherwise, a machine arbor or a square can be used, Figure 26-43. Angular settings can be made with the protractor head and steel rule of a combination set. 4. Wipe the jaws and the bottom of the vise clean with a shop rag or towel. Place the work on clean paral- lels in the vise. Tighten the jaws and tap the work onto the parallels with a mallet or soft-faced ham- mer. Use paper strips to check whether the work is on the parallels solidly, Figure 26-44. Protect the vise jaws with soft metal strips if the work is rough. 5. Select an appropriate arbor. Wipe the arbor taper and the spindle opening with a clean shop towel. Place the arbor in the spindle opening and draw it in tightly with the draw-in bar. 6. Use the smallest cutter diameter possible, Figure 26-45. It should be large enough to provide adequate clearance. SAFETY NOTE SAFETY NOTE your hands from the cutter teeth. 7. Place the cutter on the arbor as close to the column as the work will permit and key it to the shaft. If a helical slab mill cutter is used, mount it so the cutting pressure forces it toward the column. 8. Position and lock the arbor support into place, Figure 26-46. Tighten the arbor nut next. 9. Adjust the machine to the proper cutting speed and feed. SAFETY NOTE SAFETY NOTE 10. 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. Set the micrometer dial to 0. Back the work away from the rotating cutter and raise the table the required distance. 11. 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. Stopping the work causes a slight depression to be made in the machined surface. SAFETY NOTE SAFETY NOTE cut is in progress or while the cutter is rotating. 12. Complete the cut. Stop the cutter. Return the work to the starting position. Never feed the work back under the rotating cutter. 13. Following these directions, make the number of cuts necessary to bring the machined surface to size.