Owner's Manual

T-8420B, 8450B, 8720B, 8750B

CONTENTS

1. NAMES OF MAJOR PARTS................ 1

2. MACHINE SPECIFICATIONS .............. 2

3. TABLE AND MOTOR........................... 3

4. INSTALLATION ................................... 4

4-1. Installation ...................................................... 5

4-2. Lubrication...................................................... 11

4-3. Checking the machine pulley rotating direction .... 13

4-4. Alarm display (Semi dry type) ........................ 13

5. PREPARATION BEFORE SEWING .... 14

5-1. Installing the needle ....................................... 14

5-2. Removing the bobbin ..................................... 15

5-3. Winding the lower thread ............................... 16

5-4. Installing the bobbin ....................................... 17

5-5. Threading the upper thread............................ 19

5-6. Adjusting the stitch length .............................. 21

5-7. Using the knee lifter ....................................... 21

5-8. Corner sewing method (T-8450B, 8750B)...... 22

5-8-1. To stop the needle bars

(right and left) ...................................... 22

5-8-2. Number of stitches: quick-reference

guide.................................................... 22

6. SEWING ............................................... 23

6-1. Sewing............................................................23

6-2. Backtacking ....................................................23

6-3. Sewing condensed stitches ............................24

7. THREAD TENSION .............................. 25

7-1. Adjusting the thread tension ...........................25

7-2. Adjusting the presser foot pressure ................26

7-3. Adjusting the thread take-up amount..............27

8. CLEANING ........................................... 28

8-1. Daily cleaning procedures ..............................28

8-2. Lubricating via the oil cover

(every 6 months).............................................29

8-3. Applying grease - When the GREASE

indicator illuminates (Semi dry type)...............30

9. ADJUSTING THE ROTARY HOOK

LUBRICATION AMOUNT .................... 33

10. TROUBLESHOOTING ....................... 34