Double Thread Sewing Machine Manual

The Double Thread Sewing Machine is a professional-grade sewing device designed for heavy-duty stitching applications. Featuring dual-thread lockstitch technology, adjustable stitch length and width, built-in thread cutter, automatic bobbin winding, variable speed control, LED work light, and multiple presser feet compatibility. Below are key sections for safety, features, setup, operation, maintenance, and troubleshooting.

Features at a Glance

Key components: Heavy-duty metal frame, dual-thread mechanism, adjustable presser foot, built-in bobbin winder, stitch length/width controls, reverse stitch function, free arm capability.

Installation & Setup

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

1. Assemble machine head: Attach to base using provided screws.
2. Install foot pedal: Connect to machine power port.
3. Connect power: Plug into standard 120V AC outlet.
4. Install needle: Loosen needle clamp, insert needle with flat side to back.
5. Oil machine: Apply 2-3 drops of sewing machine oil to designated points.

WARNING! Machine is heavy; use proper lifting technique. Ensure stable surface to prevent tipping.

First-Time Operation

Power on machine; test basic functions before sewing.

1. Thread upper path: Follow numbered guides from spool to needle.
2. Wind bobbin: Place empty bobbin on winder, thread through tension disc.
3. Insert bobbin: Drop bobbin into case with thread pulling counterclockwise.
4. Test stitch: Use scrap fabric to test stitch quality and tension.
5. Adjust tension: Turn dial until stitches are balanced on both sides.

CAUTION! Keep fingers away from moving needle. Always use proper needle guard.

Technical Specifications

• Stitch Type: Lockstitch (double thread)
• Max Stitch Length: 5mm
• Max Stitch Width: 7mm
• Speed: Up to 1,000 stitches per minute
• Needle System: 15x1 (HAx1)
• Bobbin Type: Class 15 transparent
• Presser Foot Lift: 12mm
• Work Space: Free arm with 140mm throat space
• Power Requirements: 120V AC, 60Hz, 85W
• Weight: 15.4 lbs (7 kg)
• Dimensions: 15.7" x 7.1" x 12.2"

Controls and Settings

Main controls located on machine body and foot pedal.

Machine Controls: Power switch, stitch length dial, stitch width dial, reverse stitch lever, bobbin winder, thread tension dial, presser foot lever.

Foot Pedal: Variable speed control - press lightly for slow speed, firmly for higher speed.

Stitch Length: 0-5mm adjustment for fabric thickness. Stitch Width: 0-7mm for zigzag patterns. Thread Tension: Adjust for different thread types and fabrics. Reverse Stitch: Engage for backstitching at beginnings and ends.

Threading Procedures

Proper threading is essential for optimal performance.

1. Upper threading: Raise presser foot, follow numbered path from spool pin to needle.
2. Bobbin winding: Place spool on pin, thread through guide, wrap around bobbin 3-4 times.
3. Bobbin insertion: Open bobbin cover, drop bobbin in with thread pulling counterclockwise.
4. Bring up bobbin thread: Hold upper thread, turn handwheel toward you until bobbin thread appears.

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

Stitch Selection & Adjustment

Machine offers straight stitch, zigzag, and decorative patterns.

1. Straight stitch: Set width to 0, length 2-3mm for general sewing.
2. Zigzag stitch: Adjust width for seam finishing or stretch fabrics.
3. Buttonhole: Use buttonhole foot and follow marked guidelines.
4. Reverse stitching: Engage lever at start and end of seams.
5. Tension adjustment: Balanced when threads lock in middle of fabric.

WARNING! Do not change stitch type while needle is in fabric. Always raise needle first.

Maintenance & Cleaning

Regular maintenance ensures long machine life.

1. Daily: Brush out lint from bobbin area and feed dogs.
2. Weekly: Oil designated points with sewing machine oil.
3. Monthly: Clean tension discs with soft brush.
4. As needed: Replace needle after 8-10 hours of sewing.

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

Safety Information

Always follow safety guidelines to prevent injury.

• Keep fingers away from moving needle
• Unplug when not in use or during maintenance
• Use proper needle guard
• Do not sew over pins
• Ensure adequate lighting
• Keep hair and loose clothing away from moving parts

Regulatory Information

UL Listed: Complies with UL Standard 1270. FCC Part 15: Class B digital device. CE Certified: Meets European safety standards. Copyright © 2025 Sewing Machine Co.; all rights reserved. For technical support, visit www.sewingmachinemanual.com or contact 1-800-555-1234.

Troubleshooting

Reset: Unplug for 5 minutes to reset electronic controls.

Service: 1-800-555-1234; www.sewingmachinemanual.com