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CONSEW 99R and 99R-3 SEWING MACHINE
Straight and Zigzag Sewing

Aircrew Survival Equipmentman 2 - Aviation theories and other practices
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you with your right hand until the needle moves down and up again to its highest position. 3. Pull the needle thread gently and the bobbin thread will come up with it through the hole in the needle plate. 4. Place both ends of the thread beneath and in back of the presser foot. 5. With the needle at its highest point, place the material to be sewn beneath the presser foot and fully lower the presser foot lifter lever. 6. Start sewing. Regulating the Tension Tension is the key word to good sewing. For perfect stitching, the tension of the upper and lower threads should be balanced and just sufficiently tight to lock both threads in the center of the material (look again at figure 9-16). The machine is correctly adjusted to make a perfect stitch before leaving the factory. When adjustments do become necessary, the problem is more likely to be caused by the upper thread tension, so always begin there. To adjust the upper thread tension, proceed as follows: 1. Lower the presser foot. Remember upper thread tension adjustments must be made with the presser foot down. 2. Check the upper thread tension. If it is loose, turn the tension nut (A in fig. 9-43) 239.452 Figure 9-43.—Upper thread tension. clockwise to increase the tension; if the upper thread tension is tight, turn the tension nut counterclockwise to loosen it. Adjusting the Bobbin Thread Tension When you find it necessary to adjust the bobbin thread tension, turn the tension screw (T of fig. 9-44) on the bobbin case clockwise to increase the tension, and turn the screw counterclockwise to decrease the tension. Regulating the Pressure of the Presser Foot The pressure of the presser foot should be adjusted according to the type of material being sewn. The heavier the material, the heavier the pressure. The lighter the material, the lighter the pressure. The pressure should be only heavy enough to prevent the material from rising with the needle and to enable the feeder mechanism to move the work along evenly. The pressure becomes tighter as the regulating thumbscrew is turned clockwise, and looser as the thumbscrew is turned counterclockwise (fig. 9-45). 239.453 Figure 9-44.—Bobbin thread tension. 239.454 Figure 9-45.—Adjusting the presser foot pressure. 9-35







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