Blooy 20717004 Upper and 20717005 Lower Looper Instruction Manual

1. Introduction

This manual provides essential information for the installation, operation, and maintenance of the Blooy 20717004 Upper Looper and 20717005 Lower Looper. These components are genuine replacement parts designed for specific JACK industrial overlock sewing machine models. Proper installation and care are crucial for optimal machine performance and stitch quality.

2. Product Components

The product includes one set of upper and lower loopers. Each looper is identified by a unique part code.

• Upper Looper: Part Code 20717004
• Lower Looper: Part Code 20717005

Figure 1: Blooy 20717004 Upper Looper and 20717005 Lower Looper shown together. These are critical components for forming stitches in an overlock sewing machine.

2.1. Upper Looper (Part Code: 20717004)

Figure 2: The Blooy 20717004 Upper Looper. This component is responsible for carrying the upper thread to form the loop for the needle thread to pass through.

Figure 3: Side view of the Blooy 20717004 Upper Looper, showing its curved design for precise thread handling.

2.2. Lower Looper (Part Code: 20717005)

Figure 4: The Blooy 20717005 Lower Looper. This component works in conjunction with the upper looper to create the interlocking stitch formation.

Figure 5: Another view of the Blooy 20717005 Lower Looper, highlighting its specific shape and attachment points.

3. Compatibility

These Blooy loopers (Part Codes 20717004 and 20717005) are specifically designed for the following JACK Industrial Overlock Sewing Machine models:

• JACK JK-798
• JACK JK-798D
• JACK JK-798E
• JACK C3
• JACK C4
• JACK C5
• JACK E4
• JACK E4S

Using these loopers with incompatible machine models may result in improper function, damage to the machine, or poor stitch quality.

4. Installation (Setup)

Replacing loopers on an industrial overlock sewing machine requires precision and familiarity with the machine's mechanics. It is highly recommended that installation be performed by a qualified sewing machine technician. If you choose to perform the installation yourself, proceed with caution and refer to your specific JACK sewing machine's official service manual for detailed, model-specific instructions.

General Installation Guidelines:

1. Safety First: Always turn off and unplug the sewing machine before attempting any installation or maintenance.
2. Access the Looper Area: Open the necessary covers on your machine to gain access to the looper mechanism.
3. Remove Old Loopers: Carefully loosen the screws holding the old upper and lower loopers in place and remove them. Note their exact positioning and orientation.
4. Install New Loopers: Position the new Blooy 20717004 Upper Looper and 20717005 Lower Looper into their respective slots. Ensure they are correctly oriented according to your machine's manual.
5. Secure Loopers: Gently tighten the retaining screws. Do not overtighten, as this can strip threads or damage the loopers.
6. Timing and Adjustment: This is the most critical step. Loopers must be precisely timed with the needles to ensure proper stitch formation. Refer to your machine's service manual for exact timing procedures, clearances, and adjustments. Incorrect timing will lead to skipped stitches, thread breakage, or machine damage.
7. Test Stitching: After installation and adjustment, reassemble the machine covers, plug it in, and perform test stitching on scrap fabric. Observe the stitch quality and make any fine adjustments as needed.

Note: The specific steps and tools required may vary depending on your JACK machine model. Always prioritize the instructions in your machine's dedicated service manual.

5. Operation

Once the Blooy loopers are correctly installed and timed, they will function as integral parts of your industrial overlock sewing machine. The primary "operation" of these parts is their seamless interaction with the machine's other components to form stitches.

• Ensure proper threading of the machine, paying close attention to the looper threading paths as specified in your machine's user manual.
• Use appropriate thread types and tensions for your fabric and desired stitch.
• Regularly inspect the stitch quality. Any inconsistencies may indicate a need for re-timing or further adjustment.

6. Maintenance

To ensure the longevity and optimal performance of your Blooy loopers and your sewing machine, follow these maintenance guidelines:

• Regular Cleaning: Periodically clean the looper area to remove lint, dust, and thread fragments. Use a soft brush or compressed air. Ensure the machine is unplugged before cleaning.
• Lubrication: Apply a small amount of high-quality sewing machine oil to the moving parts of the loopers and their pivot points, as recommended by your JACK machine's manual. Avoid over-oiling.
• Inspection: Regularly inspect the loopers for any signs of wear, bending, nicks, or burrs. Damaged loopers can cause skipped stitches, thread breakage, or fabric damage and should be replaced promptly.
• Proper Storage: If the machine is to be stored for an extended period, ensure it is clean and lightly oiled to prevent rust.

7. Troubleshooting

If you experience issues after installing new loopers, consider the following common troubleshooting steps:

• Skipped Stitches:
  • Incorrect looper timing or clearance. Refer to Section 4 for adjustment.
  • Improper threading of the machine. Re-thread carefully.
  • Bent or damaged needle. Replace with a new, correct size needle.
  • Damaged looper tip. Inspect and replace if necessary.
• Thread Breakage (Looper Threads):
  • Excessive thread tension. Adjust looper thread tension.
  • Rough spots or burrs on the looper or thread path. Inspect and smooth or replace.
  • Poor quality thread. Use high-quality thread suitable for industrial machines.
  • Incorrect looper timing.
• Poor Stitch Quality (Loose, Uneven Stitches):
  • Incorrect thread tension settings. Adjust all thread tensions.
  • Improperly seated loopers. Recheck installation.
  • Lint or debris in tension discs or thread paths. Clean thoroughly.

If problems persist after attempting these troubleshooting steps, it is advisable to consult a professional sewing machine technician or refer to your machine's comprehensive service manual.

8. Specifications

9. Warranty and Support

Specific warranty information for the Blooy 20717004 Upper Looper and 20717005 Lower Looper is not provided in this document. For details regarding warranty coverage, returns, or technical support, please contact the seller or the manufacturer directly. Ensure you retain your proof of purchase for any warranty claims.