Janome MyLock 644D Serger Manual

The Janome MyLock 644D is a professional-grade 3/4 thread serger with differential feed, built-in rolled hem capability, color-coded threading system, easy stitch selection, and adjustable cutting width. Features include built-in rolled hem, easy-to-use color-coded threading, differential feed for perfect fabric handling, adjustable stitch length and width, and free arm capability. Below are key sections for safety, features, setup, operation, maintenance, and troubleshooting.

Features at a Glance

Key components: Color-coded threading system, Differential feed mechanism, Built-in rolled hem, Adjustable stitch length and width, Free arm capability, Built-in thread cutter.

Unpacking and Setup

Unpack and inspect all contents. Place on stable sewing surface.

1. Remove serger from packaging: Carefully lift machine from box.
2. Install accessories: Attach extension table if included.
3. Thread stand setup: Position thread stand behind machine.
4. Power connection: Plug into appropriate electrical outlet.
5. Needle installation: Install appropriate needles following color coding.

WARNING! Machine is heavy; lift with care to avoid injury. Ensure all connections are secure.

First-Time Operation

Power on serger; follow threading sequence carefully.

1. Thread the machine: Follow color-coded threading path for upper and lower loopers, needles.
2. Test stitching: Use scrap fabric to test stitch quality and tension.
3. Adjust tension: Use tension dials to achieve balanced stitches.
4. Set differential feed: Adjust based on fabric type being used.
5. Practice basic seams: Create sample seams to familiarize with machine operation.

CAUTION! Keep fingers away from moving needles and cutting blade during operation.

Specifications

• Machine Type: 3/4 Thread Serger with Differential Feed
• Stitch Types: 4-thread overlock, 3-thread overlock, 2-thread overlock, rolled hem
• Stitch Length: 1.0mm to 4.0mm adjustable
• Stitch Width: 2.0mm to 7.0mm adjustable
• Differential Feed Ratio: 0.7 to 2.0
• Maximum Speed: 1300 stitches per minute
• Needles: HAx1 SP system needles (included)
• Power Source: 110V AC, 60Hz
• Weight: Approximately 15.4 lbs (7 kg)
• Dimensions: 13.4" x 11.8" x 12.6"

Controls and Settings

Access controls via front panel dials and levers. Main Controls: Power switch, Stitch length dial, Stitch width dial, Differential feed dial, Tension dials (4), Rolled hem lever.

Adjustment Points: Upper looper tension, Lower looper tension, Needle thread tension, Stitch length, Stitch width, Differential feed, Cutting width, Rolled hem conversion.

Tension Settings: Upper looper (2-4), Lower looper (3-5), Needles (3-4). Stitch Length: 1.0mm (rolled hem) to 4.0mm (heavy fabrics). Differential Feed: 0.7 (gathering) to 2.0 (stretching prevention).

Threading the Serger

Follow color-coded threading path for proper operation.

1. Turn off power before threading.
2. Follow color sequence: Yellow (upper looper), Green (lower looper), Blue (right needle), Red (left needle).
3. Raise presser foot to open tension discs.
4. Thread in correct order: Upper looper first, then lower looper, then needles.
5. Test thread path by gently pulling threads to ensure smooth movement.

Tip: Always thread with presser foot raised to ensure proper tension disc engagement.

Stitch Selection and Adjustment

Supports multiple stitch types for various sewing applications.

1. 4-thread overlock: For strong seams on woven fabrics.
2. 3-thread overlock: For lighter weight fabrics and decorative edges.
3. 2-thread overlock: For lightweight fabrics and narrow seams.
4. Rolled hem: For narrow rolled edges on lightweight fabrics.
5. Differential feed adjustment: Use for stretch fabrics, knits, or to prevent puckering.
6. Stitch length adjustment: Shorter for fine fabrics, longer for heavy materials.
7. Stitch width adjustment: Narrow for lightweight fabrics, wider for heavy materials.

WARNING! Always test stitch settings on scrap fabric before working on your project.

Maintenance and Cleaning

Unplug before cleaning and maintenance. Regular cleaning ensures optimal performance.

1. Daily cleaning: Remove lint from looper area and feed dogs.
2. Weekly maintenance: Oil machine according to manufacturer's instructions.
3. Blade care: Keep cutting blade clean and sharp.
4. Needle replacement: Replace needles regularly or when damaged.
5. Professional servicing: Annual professional maintenance recommended.

CAUTION! Always unplug machine before cleaning or maintenance. Use only recommended oils.

Regulatory Information

UL Listed: Complies with UL safety standards for sewing machines. Copyright © 2025 Janome; trademarks of Janome Sewing Machine Co., Ltd. For support, visit www.janome.com or contact 1-800-631-0183. Made in Taiwan. This product meets all applicable safety standards for household sewing machines.

Troubleshooting

Reset: Turn machine off and on; re-thread completely if problems persist.

Service: 1-800-631-0183; www.janome.com