Janome MyLock 334D Serger Manual

The Janome MyLock 334D is a professional-grade 3/4 thread serger with differential feed, built-in rolled hem capability, color-coded threading system, easy stitch selection, and free-arm capability. Features include adjustable stitch length (0.5-4mm), stitch width (3-7mm), cutting width (2.5-7mm), differential feed ratio (0.7-2.0), and built-in rolled hem for professional finishes. 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, free-arm design, built-in rolled hem, stitch length/width controls, cutting width adjustment.

Installation & Setup

Unpack and inspect contents. Place on stable sewing table.

1. Remove packaging materials and protective covers from machine.
2. Install presser foot: Align presser foot with ankle and lower presser foot lever.
3. Connect power: Plug power cord into machine and electrical outlet.
4. Install needles: Use standard household sewing machine needles (size 11/80 recommended).
5. Wind and install loopers: Follow color-coded threading diagram.

WARNING! Keep fingers away from cutting blade during setup and operation. Always unplug machine when threading or changing needles.

First-Time Operation

Power on serger; follow threading sequence carefully.

1. Thread upper looper: Follow red color coding and numbered guides.
2. Thread lower looper: Follow blue color coding and numbered guides.
3. Thread needles: Follow green color coding for right needle.
4. Set stitch type: Use stitch selection dial for desired stitch.
5. Test on fabric scrap: Adjust tensions as needed for balanced stitch.
6. Practice basic serging: Begin with straight seams on woven fabric.

CAUTION! Always use the handwheel to bring needles to highest position before starting. Keep fingers clear of cutting area.

Specifications

• Type: 3/4 Thread Serger with Differential Feed
• Stitch Types: Overlock, rolled hem, flatlock, decorative
• Stitch Length: 0.5mm to 4mm adjustable
• Stitch Width: 3mm to 7mm adjustable
• Cutting Width: 2.5mm to 7mm adjustable
• Differential Feed Ratio: 0.7 to 2.0
• Speed: Up to 1300 stitches per minute
• Needles: Standard household sewing machine needles
• Power Requirements: 120V AC, 60Hz
• Dimensions: Standard serger size with free-arm capability

Controls and Settings

Access controls via front panel and side adjustments. Main Controls: Power switch, stitch length dial, stitch width dial, differential feed dial, tension controls.

Adjustment Dials: Upper looper tension, lower looper tension, needle tension, presser foot pressure.

Stitch Selection: Overlock (3-4 thread), rolled hem, flatlock, decorative stitches. Differential Feed: Adjust for stretching (lower ratio) or gathering (higher ratio). Tension Settings: Balanced for most fabrics (normal setting 4), adjust for specialty fabrics.

Threading the Serger

Follow color-coded system: Red for upper looper, blue for lower looper, green for needles.

1. Raise presser foot and turn handwheel to highest needle position.
2. Thread upper looper: Follow red guides 1 through 6.
3. Thread lower looper: Follow blue guides 1 through 6.
4. Thread needles: Follow green guides for right needle position.
5. Pull all threads under presser foot toward back of machine.
6. Test stitch on fabric scrap and adjust tensions as needed.

Tip: Always thread with presser foot raised to release tension disks. Use tweezers for difficult threading areas.

Stitch Selection & Techniques

Supports multiple stitch types for various sewing applications.

1. Basic Overlock: Use for seam finishing and construction.
2. Rolled Hem: Convert for delicate edge finishing on sheers.
3. Flatlock: Create decorative seams for activewear and knit fabrics.
4. Differential Feed: Use lower ratio for stretch fabrics, higher for gathering.
5. Decorative Stitches: Use woolly nylon thread for decorative effects.
6. Gathering: Set differential feed to 2.0 for automatic gathering.
7. Lettuce Edge: Use on stretch fabrics with differential feed for decorative edge.
8. Coverstitch: Can be converted for coverstitch applications with proper setup.

WARNING! Always test stitches on fabric scrap before sewing project. Never force fabric through machine.

Maintenance & Cleaning

Unplug before cleaning. Remove lint buildup regularly with brush provided.

1. Daily: Brush out lint from loopers and feed dogs.
2. Weekly: Oil machine according to lubrication points diagram.
3. Monthly: Check and replace needle if dull or damaged.
4. As needed: Replace cutting blade when dull (professional service recommended).

CAUTION! Use only Janome recommended oil. Never use compressed air to clean machine as it can force lint deeper into mechanism.

Regulatory Information

UL Listed: Complies with safety standards for household sewing machines. Copyright © Janome America, Inc. For support, visit www.janome.com or contact 1-800-631-0183. Made for household use. Not intended for commercial or industrial applications.

Troubleshooting

Reset: Complete re-threading often resolves most issues.

Service: 1-800-631-0183; www.janome.com for authorized service centers.