Free Singer 621B Sewing Machine Manual

The Singer 621B is a versatile household sewing machine featuring straight and zigzag stitching, built-in buttonholer, free arm capability, adjustable stitch length and width, built-in light, reverse stitching, and drop feed for darning and embroidery. Powered by 120V AC, this mechanical sewing machine includes presser feet, bobbins, needles, and instruction manual. Below are key sections for safety, features, setup, operation, maintenance, and troubleshooting.

1. Features at a Glance 2. Unpacking and Setup 3. First-Time Operation 4. Specifications 5. Controls and Settings 6. Stitch Selection 7. Threading and Bobbin 9. Maintenance & Cleaning 10. Regulatory Information 11. Troubleshooting

Features at a Glance

Key components: Mechanical sewing head, stitch selection dial, tension control, bobbin winder, free arm, built-in light, foot pedal control.

FeatureDescription
Stitch selection dialSelects straight stitch, zigzag, and decorative patterns
Stitch length controlAdjusts stitch length from 0-4mm
Stitch width controlAdjusts zigzag width from 0-5mm
Reverse stitch leverReinforces stitching at beginning and end
Bobbin winderWinds bobbin automatically while machine is threaded
Free armRemovable accessory compartment for sewing cuffs and sleeves
Built-in lightIlluminates sewing area
Tension control dialAdjusts upper thread tension
Presser foot pressureAdjustable for different fabric thicknesses
Drop feed dogsLowers feed dogs for darning and embroidery

Unpacking and Setup

Unpack and inspect contents. Place on stable surface at comfortable height.

  1. Remove machine from packaging: Lift carefully from carrying case.
  2. Position machine: Place on sturdy table with 6 inches clearance behind.
  3. Connect foot pedal: Plug into machine's pedal socket.
  4. Connect power: Plug power cord into 120V AC outlet.
  5. Install needle: Loosen needle clamp, insert needle with flat side to back.
  6. Attach presser foot: Lift lever, snap foot into place.

WARNING! Machine is heavy; lift with care to avoid injury. Ensure stable surface.

First-Time Operation

Power on machine; follow threading diagram.

  1. Wind bobbin: Place empty bobbin on winder, thread through tension disc.
  2. Thread upper thread: Follow numbered guides from spool to needle.
  3. Insert bobbin: Drop bobbin into case with thread moving counterclockwise.
  4. Pull up bobbin thread: Hold upper thread, turn hand wheel toward you.
  5. Select stitch: Turn dial to straight stitch for practice.
  6. Test sew: Place fabric under presser foot, lower foot, press pedal gently.

CAUTION! Keep fingers away from needle during operation. Always unplug when not in use.

Specifications

Controls and Settings

Main controls located on front and side of machine.

Front Panel: Stitch selection dial, stitch length control, stitch width control, reverse stitch lever, bobbin winder, tension control dial.

Stitch Selection: Turn dial to select pattern (straight, zigzag, blind hem, stretch). Stitch Length: 0-4mm (0 for darning, 4 for basting). Stitch Width: 0-5mm for zigzag patterns. Tension: 0-9 (4-5 normal, lower for stretch fabrics, higher for dense fabrics). Presser Foot Pressure: Adjust screw above needle bar for thick/thin fabrics.

Stitch Selection

Select appropriate stitch for fabric and project type.

  1. Straight Stitch: Dial position 1 - general sewing, topstitching
  2. Zigzag Stitch: Dial position 2-4 - finishing edges, stretch fabrics
  3. Blind Hem: Dial position 5 - nearly invisible hemming
  4. Stretch Stitch: Dial position 6 - reinforced seams for knits
  5. Decorative: Dial positions 7-8 - decorative patterns
  6. Buttonhole: Dial position 9 - automatic 1-step buttonhole

Tip: Always test stitch on fabric scrap before starting project.

Threading and Bobbin

Proper threading essential for good stitch quality.

  1. Upper Threading: Raise presser foot, follow numbered guides from spool pin to needle.
  2. Bobbin Winding: Place spool on pin, thread through guides to bobbin, push bobbin to right.
  3. Bobbin Insertion: Open cover, drop bobbin in case with thread counterclockwise.
  4. Thread Drawing: Hold upper thread, turn hand wheel to catch bobbin thread.
  5. Tension Adjustment: Balanced tension shows equal thread on both sides of fabric.

WARNING! Ensure presser foot is raised when threading to engage tension discs.

Maintenance & Cleaning

Unplug before maintenance. Clean lint regularly for optimal performance.

  1. Daily: Brush lint from bobbin area and feed dogs.
  2. Weekly: Oil hook race and moving parts with sewing machine oil.
  3. Monthly: Clean tension discs with folded fabric or dental floss.
  4. Needles: Replace after 8 hours of sewing or if damaged.
  5. Storage: Cover machine when not in use to prevent dust accumulation.

CAUTION! Use only sewing machine oil. Never use household oils.

Regulatory Information

UL Listed: Certified for household use in North America. Copyright © Singer Manufacturing Company. Patents pending. For support, visit www.singer.com or contact 1-800-4-SINGER. Made for 120V AC, 60Hz operation only.

Troubleshooting

SymptomPossible CauseCorrective Action
Thread breakingIncorrect threading/tensionRethread completely; reduce tension; check for burrs on needle.
Skipped stitchesWrong needle/damaged needleReplace needle; ensure correct type for fabric.
Uneven stitchesPoor feeding/tensionClean feed dogs; adjust presser foot pressure; balance tension.
Machine jamsThread jam in bobbinRemove bobbin case; clean out tangled thread; reinsert properly.
Noise during operationLack of oil/lint buildupClean and oil machine; check for loose parts.
Needle hits presser footIncorrect needle positionEnsure needle is fully up and inserted correctly; check foot attachment.

Reset: Unplug for 5 minutes if electronic issues occur.

Service: 1-800-4-SINGER; www.singer.com

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