Class 99 & 99K
To Regulate Pressure on Presser Foot
For ordinary sewing, the pressure of the presser foot on the material seldom requires changing. Heavy materials require more pressure than light weight materials. The pressure should be only heavy enough to prevent the material from rising with the needle and to enable the feed to move the work along evenly without side creeping. To increase the pressure, turn the thumb screw W, Fig. 25 clockwise or downward. To lighten the pressure, turn the thumb screw W so that it screws upward.
Thread Tension
For perfect stitching, the tension on the needle and bobbin threads must be heavy enough to pull the threads to the center of the thickness of the material and make a firm stitch, as shown in Fig 26. If the needle lies straight along the top side of the material, the tension on the needle thread is too heavy or the tension on the bobbin thread is too light, as shown in Fig 27. If the bobbin thread lies straight along the underside of the material, the tension on the needle thread is too light or the tension on the bobbin thread is too heavy, as shown in
Fig. 28.
FIG. 25 Thumb Screw for Regulating Pressure
on Presser Foot
FIG. 26 Perfect Stitching
FIG. 27 Imperfect Stitching
FIG. 28 Imperfect Stitching
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