23.7.1 Relief Cuts Relief cuts allow waste material to break loose as you saw the workpiece. Each cut is made through excess material almost to the cutting line. See Figure 23-40. Both band saw and scroll saw operations require relief cuts for making curves when: • There is a sharp inside or outside curve. • The curve changes direction: left to right or right to left. • Cabinet parts will be cut from large pieces of stock. The excess material may be difficult to control. Make relief cuts at least every 4″ to 6″ (100 mm to 150 mm). When excess material is removed with relief cuts, there is less chance the blade will twist or break. With relief cuts, you do not need to pull the workpiece back through a long, irregular kerf. 23.8 Band Saw A band saw is a very versatile machine. See Figure 23-41. Besides making irregular curves and arcs, it can rip, bevel, and resaw. Install a rip fence or use a miter gauge for these operations. With the appropriate jig, the band saw can cut complete circles. Safety in Action Using the Radial Arm Saw • Wear eye protection. • Remove jewelry secure long hair and loose clothing. • Hold stock firmly on the table and against the fence for all crosscutting operations. Support long boards and wide panels. • Be certain that all clamps and locking devices are tight and the depth of cut is correct before starting the motor. • Always return the saw to the rear of the table after completing a crosscut or miter cut. Do not remove stock from the table until the saw has returned and the blade has stopped. • Always keep your hands 3″ to 4″ (76 mm to 100 mm) from the blade. • Shut off the motor, wait for the blade to stop, and disconnect power before making any adjustments. • Clean the table of scraps or sawdust before and after using the machine. Goodheart-Willcox Publisher Figure 23-39. There is a minimum cutting radius for each band or scroll saw blade width. Goodheart-Willcox Publisher Figure 23-40. Relief cuts are made to irregular curves. Minimum Recommended Kerf Radius 7 1/4 5 7/16 3 3/4 2 1/2 1 1/16 5/8 1/8 3/4 1 5/8 1/2 3/8 1/4 1/8 Blade Size Relief cuts Cutting lines 390 Section 4 Machining Processes Copyright Goodheart-Willcox Co., Inc. Recutting Saw Kerfs The procedure is as follows: 1. With the switch off, disconnect power to the saw. 2. Raise the blade above the table’s surface. 3. Position the motor-blade assembly over the center of the table for the crosscut, miter, or bevel setting. 4. Tighten the rip and yoke locks. 5. Lower the blade until it touches the table protec- tor. Then raise it 1/16″ (1.5 mm). Note how far you turn the lever while raising the blade. 6. Tighten arm adjustments. 7. Connect power and start the saw. Allow it to reach full speed. 8. Lower the blade twice as far as you raised it. The cut will be 1/16″ (1.5 mm) into the table protector. 9. Hold the handle securely and loosen the rip lock. 10. With a tight grip on the handle, push the blade slowly toward the column and cut through the fence. The machine is now ready for use. Procedure