Janome MyLock 434D Overlocker Manual

The Janome MyLock 434D is a professional-grade 3/4 thread overlocker with differential feed, built-in rolled hem capability, color-coded threading system, free arm capability, built-in thread cutter, adjustable stitch length (1-4mm) and width (3.5-7mm), maximum speed of 1300 stitches per minute, and built-in needle threader. Below are key sections for safety, features, setup, operation, maintenance, and troubleshooting.

1. Features at a Glance 2. Unpacking and Setup 3. Threading the Overlocker 4. Specifications 5. Controls and Settings 6. Basic Operation 7. Stitch Selection 8. Maintenance and Care 9. Accessories 10. Warranty Information 11. Troubleshooting

Features at a Glance

Key components: Upper looper, Lower looper, Right needle, Left needle, Differential feed system, Stitch length/width dials, Tension discs, Free arm, Built-in light.

FeatureDescription
Differential FeedAdjustable from 0.7 to 2.0 for perfect fabric handling
Built-in Rolled HemEasy conversion for delicate edge finishing
Color-coded ThreadingSimplified threading with visual guides
Free Arm CapabilityFor sewing cuffs and small circular items
Built-in Thread CutterConvenient thread trimming at front of machine
Adjustable Presser FootPressure control for different fabric types
Stitch Length DialAdjustable from 1mm to 4mm
Stitch Width DialAdjustable from 3.5mm to 7mm
Built-in Needle ThreaderEasy needle threading for upper looper
Drop FeedFor decorative stitching and darning

Unpacking and Setup

Unpack and inspect all components. Place on stable, level surface.

  1. Remove packaging materials and protective covers from machine.
  2. Attach accessory box and ensure all parts are present.
  3. Install foot controller and connect to power source.
  4. Install needles following color coding (right needle - red, left needle - blue).
  5. Oil machine according to lubrication points diagram.

WARNING! Machine is heavy; lift with care using both hands. Ensure stable surface to prevent tipping.

Threading the Overlocker

Follow color-coded threading system for proper setup.

  1. Upper looper (green): Thread through green guides and tension disc.
  2. Lower looper (blue): Thread through blue guides and tension disc.
  3. Right needle (red): Thread through red guides and eye of needle.
  4. Left needle (blue): Thread through blue guides and eye of needle.
  5. Pull all threads under presser foot and toward back of machine.

CAUTION! Always raise presser foot when threading to open tension discs.

Specifications

Controls and Settings

Main controls located on front and side of machine.

Front Panel: Stitch length dial, Stitch width dial, Differential feed dial, Looper thread tension dials, Needle thread tension dials, Power switch, Built-in light switch.

Stitch Length: 1mm (short) to 4mm (long). Stitch Width: 3.5mm (narrow) to 7mm (wide). Differential Feed: 0.7 (gathering) to 2.0 (stretching). Tension: 0-9 scale for each thread path. Rolled Hem: Lever for easy conversion between standard and rolled hem stitching.

Basic Operation

Starting your first overlock project.

  1. Select appropriate stitch for your fabric type.
  2. Set tension dials to recommended settings for chosen stitch.
  3. Place fabric under presser foot, lower presser foot lever.
  4. Depress foot controller to begin stitching.
  5. Guide fabric gently, allowing feed dogs to move fabric.
  6. Use built-in thread cutter to trim threads when finished.

Tip: Practice on fabric scraps to test settings before starting your project.

Stitch Selection

Available stitch types and their applications.

  1. 4-thread safety stitch: For strong seams that require stability
  2. 3-thread overlook: Standard overlooking for most fabrics
  3. 3-thread rolled hem: For delicate fabrics and fine edges
  4. 2-thread rolled hem: Ultra-fine hemming for sheer fabrics
  5. Gathering: Use differential feed set above 1.0 with reduced tension
  6. Lettuce edge: Use differential feed set above 1.5 on stretch fabrics

WARNING! Always test stitch on fabric scrap before proceeding with project.

Maintenance and Care

Regular maintenance ensures optimal performance.

  1. Clean lint and dust from loopers and feed dogs after each use.
  2. Oil machine monthly or after every 10 hours of use.
  3. Replace needles regularly or when damaged.
  4. Check and adjust tension as needed for different fabrics.
  5. Store covered when not in use to prevent dust accumulation.

CAUTION! Always unplug machine before cleaning or maintenance.

Accessories

Standard accessories included with Janome MyLock 434D.

AccessoryPurpose
Standard Presser FootGeneral overlooking
Thread Nets (4)Prevent thread tangling
Needles (4)HAx1 SP system replacement needles
Lint BrushCleaning loopers and feed dogs
ScrewdriverNeedle replacement and adjustments
Oil BottleMachine lubrication
Spool Caps (4)Hold thread spools securely
Instruction ManualComplete operating instructions

Warranty Information

Janome MyLock 434D comes with 25-year limited warranty covering mechanical parts. Electronic components covered for 2 years. Labor covered for 1 year. Warranty registration required within 10 days of purchase. Keep original receipt as proof of purchase. For warranty service, contact authorized Janome dealer.

Troubleshooting

SymptomPossible CauseCorrective Action
Thread breakingIncorrect tension/threadingRe-thread following color codes; adjust tension settings.
Uneven stitchesDifferential feed settingAdjust differential feed; check fabric type compatibility.
Fabric not feedingPresser foot pressureAdjust presser foot pressure; clean feed dogs.
Looper thread skippingTiming issuesCheck looper timing; consult authorized service center.
Machine jammingThread buildupRemove thread jam; clean race area; re-thread properly.
Needle breakingIncorrect installationEnsure needle is fully inserted and facing correct direction.

Service: Contact authorized Janome dealer for technical support and repairs.

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

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