singer sewing machine 15-91 manual

The Singer 15-91 is a classic straight-stitch sewing machine with a powerful potted motor, renowned for its reliability and smooth operation. It features a full rotary hook, reverse stitching capability, adjustable stitch length, built-in bobbin winder, and a high-speed capability ideal for heavy fabrics. Below are key sections for safety, features, setup, operation, maintenance, and troubleshooting.

Features at a Glance

Key components: Cast-iron body, Potented Motor, Rotary Hook System, Reverse Lever, Stitch Length Regulator, Built-in Bobbin Winder, Presser Foot, Spool Pins.

Installation & Setup

Unpack and inspect contents. Place on a sturdy table or in its cabinet.

1. Position Machine: Ensure it is stable and level.
2. Connect Power: Plug the motor cord into a 120V outlet. Ensure foot controller is connected.
3. Attach Belt: Check that the motor belt is properly seated on the handwheel and motor pulley.
4. Install Needle: Insert needle with flat side to the rear, tighten screw.
5. Oil Machine: Refer to oiling chart before first use.

WARNING! Machine is heavy; lift with care. Ensure power is off during setup.

First-Time Operation

Power on machine; test without thread first.

1. Thread the Machine: Follow threading diagram (spool pin to needle).
2. Wind Bobbin: Place empty bobbin on winder, engage clutch, press foot controller.
3. Insert Bobbin: Drop bobbin into case, pull thread through slot and under tension spring.
4. Draw Up Bobbin Thread: Hold needle thread, turn handwheel toward you to catch bobbin thread.
5. Test Stitch: Use fabric scrap to test stitch length and tension.

CAUTION! Keep fingers away from needle during operation. Always turn handwheel toward you.

Specifications

• Model: Singer 15-91
• Stitch: Straight Stitch
• Stitch Length: Adjustable 0-4 mm
• Speed: Up to 1,100 stitches per minute
• Bobbin: Class 15 metal bobbin
• Needle System: 15x1 (standard domestic)
• Presser Foot: Low Shank
• Motor: Potted, 120V AC
• Weight: Approximately 30 lbs (machine head)
• Dimensions: Varies with cabinet

Controls and Adjustments

Main controls located on the right side of the machine.

Stitch Length Dial: Turn to set stitch length (higher number = longer stitch). Reverse Lever: Push to the left to sew in reverse. Tension Dial: Turn clockwise to increase upper thread tension. Presser Foot Lever: Raises and lowers the presser foot. Handwheel: Turn toward you to manually move needle. Bobbin Winder Clutch: Slide to the right to engage bobbin winding.

Adjusting Tension: Balanced stitches show threads locked in the middle of the fabric. Adjust upper tension dial first. For bobbin tension, use a small screwdriver on the bobbin case spring screw (turn slightly clockwise to increase).

Threading the Machine

Correct threading is essential for proper operation.

1. Raise needle to highest position using handwheel.
2. Place spool on spool pin.
3. Follow numbered guides: Through first thread guide, down to tension discs, up to take-up lever, down through lower guide, through needle bar guide, and finally through the eye of the needle from front to back.
4. Pull about 4 inches of thread toward the rear.

Tip: Ensure presser foot is raised when threading to allow thread to seat properly in the tension discs.

Maintenance & Oiling

Regular oiling is critical for smooth operation and longevity.

1. Use only high-quality sewing machine oil.
2. Refer to oiling points diagram (typically under face plate, in hook race, and at moving joints).
3. Apply 1-2 drops to each oiling point.
4. Run machine without thread for a minute to distribute oil.
5. Wipe away any excess oil.

Frequency: Oil after every 8-10 hours of use. WARNING! Do not over-oil. Keep oil away from belts and motor.

Needle & Bobbin Replacement

Replacing Needle: Loosen needle clamp screw, remove old needle. Insert new needle with flat side to the rear. Push up as far as it will go, then tighten screw firmly.

Replacing/Inserting Bobbin: Open slide plate. Drop bobbin into case with thread running counter-clockwise. Pull thread through slot and under tension spring. Close slide plate.

Care & Cleaning

Unplug machine before cleaning.

1. Remove needle plate and bobbin case to access lint.
2. Use a small brush to remove lint and dust from feed dogs, hook race, and tension discs.
3. Wipe exterior with a soft, dry cloth.
4. Do not use compressed air, as it can force lint deeper.

CAUTION! Never spray cleaners or lubricants directly onto the machine. Use only sewing machine oil.

Regulatory Information

Manufactured by The Singer Manufacturing Company. This vintage machine may not have modern electrical certifications. For safety, have the wiring and foot controller inspected by a qualified technician before use if condition is unknown. Singer is a registered trademark. For historical information or parts, visit singer.com or consult a certified Singer service center.

Troubleshooting

Service: For complex repairs, contact a certified vintage Singer technician.