janome overlocker 644d manual

The Janome Overlocker 644D is a professional-grade 4-thread overlock sewing machine designed for creating finished seams, rolled hems, and decorative edges. It features differential feed for handling various fabric types, built-in rolled hemming, easy threading system, adjustable stitch length and width, free arm capability, and built-in thread cutter. Below are key sections for safety, features, setup, operation, maintenance, and troubleshooting.

1. Features at a Glance 2. Installation & Setup 3. First-Time Operation 4. Specifications 5. Controls and Settings 6. Threading the Machine 7. Stitch Types and Applications 9. Care & Maintenance 10. Regulatory Information 11. Troubleshooting

Features at a Glance

Key components: 4-thread overlock capability, Differential Feed System, Built-in Rolled Hem, Free Arm, Adjustable Stitch Length (1-4mm) and Width (2.5-7mm), Built-in Thread Cutter, Easy-thread Looper System.

Feature	Description
Differential Feed	Prevents stretching or puckering on various fabrics
Built-in Rolled Hem	Easy conversion for fine rolled hems
Free Arm	For sewing cuffs, sleeves, and other tubular items
Stitch Length Dial	Adjustable from 1mm to 4mm
Stitch Width Dial	Adjustable from 2.5mm to 7mm
Built-in Thread Cutter	Convenient thread trimming at front of machine
Easy-thread Loopers	Color-coded threading path for upper and lower loopers
Presser Foot Pressure	Adjustable for different fabric weights
LED Lighting	Bright illumination of sewing area
Accessory Storage	Built-in compartment for tools and accessories

Installation & Setup

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

Remove packaging materials and protective covers from machine.
Attach extension table if included for larger sewing projects.
Install foot control pedal and connect to power source.
Insert needle properly with flat side facing back.
Wind and install bobbin following threading diagram.

WARNING! Keep fingers away from moving parts during operation. Always disconnect power when threading or changing needles.

First-Time Operation

Power on machine; test on scrap fabric first.

Thread machine following color-coded guides: upper looper (blue), lower looper (green), right needle (red), left needle (yellow).
Set differential feed to N (normal) position for standard fabrics.
Adjust stitch length and width according to fabric type.
Practice on scrap fabric to test tension settings.
Engage rolled hem function for fine edge finishing.

CAUTION! Always start with needle in highest position. Keep work area clean and well-lit.

Specifications

Machine Type: 4-thread Overlock/Serger
Stitch Types: 4-thread overlock, 3-thread overlock, rolled hem, flatlocking
Stitch Length: 1mm to 4mm adjustable
Stitch Width: 2.5mm to 7mm adjustable
Differential Feed: 0.7 to 2.0 ratio
Speed: Up to 1300 stitches per minute
Needles: HAx1 SP system needles, size 11/80
Power Requirements: 110V, 60Hz (or local voltage)
Weight: Approximately 7.5 kg (16.5 lbs)
Warranty: 25-year limited warranty

Controls and Settings

Main controls located on front and side of machine.

Front Panel: Stitch Length Dial, Stitch Width Dial, Differential Feed Dial, Rolled Hem Lever, Presser Foot Lever, Tension Dials (4), Power Switch, LED Light.

Stitch Length: Adjust from 1mm (short) to 4mm (long). Stitch Width: Adjust from 2.5mm (narrow) to 7mm (wide). Differential Feed: N position for normal fabrics, <1 for stretching, >1 for gathering. Tension Dials: Upper Looper, Lower Looper, Right Needle, Left Needle - adjust according to fabric and stitch type.

Threading the Machine

Follow color-coded threading path for proper operation.

Raise presser foot and raise needle to highest position.
Thread upper looper following blue guide path.
Thread lower looper following green guide path.
Thread right needle following red guide path.
Thread left needle following yellow guide path.
Pull all threads under presser foot toward back.

Tip: Always thread with presser foot raised to open tension discs.

Stitch Types and Applications

Multiple stitch options for various sewing needs.

4-thread Overlock: Strong seam for woven fabrics, prevents raveling
3-thread Overlock: Flexible seam for knits and stretch fabrics
Rolled Hem: Fine finished edge for lightweight fabrics
Flatlocking: Decorative seam for sportswear and activewear
Gathering: Set differential feed above 1 for gathering effect
Lettuce Edge: Stretch knit fabrics while sewing for decorative edge

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

Care & Maintenance

Regular maintenance ensures optimal performance and longevity.

Clean lint and dust from loopers and feed dogs after each use
Oil machine according to manufacturer's instructions
Replace needles regularly (every 8-10 hours of sewing)
Check and adjust tension as needed for different fabrics
Store machine covered when not in use

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

Regulatory Information

CE Certified: Complies with European safety standards. UL Listed: Meets North American electrical safety requirements. Manufactured under ISO 9001 quality standards. Copyright © Janome Corporation. For technical support and service, contact authorized Janome dealers or visit www.janome.com.

Troubleshooting

Symptom	Possible Cause	Corrective Action
Thread breaking	Incorrect threading/tension	Re-thread following color guides; adjust tension
Fabric puckering	Differential feed setting	Adjust differential feed to N position; test on scrap
Uneven stitches	Dull needle/wrong tension	Replace needle; check and adjust tension settings
Machine jams	Lint buildup/thread tangle	Clean lint from hook area; remove tangled threads
Loops on fabric	Incorrect looper threading	Re-thread loopers following color-coded guides
Skip stitches	Bent needle/wrong needle type	Replace with new HAx1 SP needle; ensure proper insertion

Service: Contact authorized Janome service center for repairs. Warranty does not cover damage from improper use or unauthorized repairs.