Operation
12
THREAD TENSION
Proper and Improper Thread Tension
Proper thread tensions are important in obtaining optimal stitch appearance, proper knot
location and tensions within the carpet being sewn.
When the upper and lower thread tensions are correct, the threads are knotted in the
center of the carpet (Figure 7).
Excessive tension on the upper thread will result in looping of the bobbin thread on the top
of the carpet (Figure 8).
Excessive tension of the lower thread will result in looping of the top thread on the bottom
of the carpet (Figure 9).
Upper Thread Adjustment
To increase thread tension, turn the tension control clockwise. Conversely, turning coun-
terclockwise will decrease tension.
Note:
Make small adjustments (
1/4
” turns or less) until desired results are achieved.
Whenever you rethread the machine, make sure the thread is properly seated between
the tension discs. Lack of upper tension can result in looping of upper thread on bottom
of carpet.
Lower Thread Adjustment
Remove bobbin case. Check that the bobbin spool is properly threaded in the case. Pull
thread into slot and under spring into notch in case.
Thread must pass through eyelet in bobbin case for proper operation as shown in Figure
10. Tension on the bobbin thread should be light.
To test tension, hold the thread end and allow the bobbin case to hang freely. Give the
thread a slight tug upward. If the tension is correct, the weight of the case will cause ap-
proximately 1” of thread to feed out.
To increase thread tension, turn the small slot screw on the case clockwise. Conversely,
turning counter clock wise will decrease tension.
Note:
Rotate the adjusting screw no more than 1/8” to 1/4” turn at a single time, until
desired result is achieved. Recheck spool threading after each test and before reinstalling
case in machine. Over time, thread dust will accumulate between the spring and case
which can cause erratic tensions. To correct, remove screw and spring and clean.
FIG. 7
FIG. 8
FIG. 9
FIG. 10