FY810 / FY820

Single / Double Needle Post-Bed Lockstitch Sewing MachineInstruction Manual

1. Machine Overview

The FY810/820 is a post-bed lockstitch sewing machine designed for shoes, handbags, leather goods, hats, wigs, and specialty materials.

Key Features

• Post-bed design for curved and three-dimensional sewing

• Full rotary horizontal shaft hook

• Slide-type thread take-up lever for consistent, well-tensioned stitches

• Roller presser allows free feeding

• Smooth, even seams on leather, sponge-backed leather, and light materials without creasing

• Easy reverse stitching with lever operation

• Simple stitch length adjustment

• Interchangeable roller presser and flat presser foot gauge set

• Double-needle model supports stable double-row stitching(needle gauge up to 12.7 mm, depending on gauge set)

2. Main Parts Identification

1. Spool Pin

2. Oil Reservoir (Right)

3. Balance Wheel

4. Stitch Regulating Dial

5. Reverse Lever

6. Post

7. Hook Post Holder

8. Hook Post Cover Plate (Back)

9. Hook Shaft Bracket

10. Slide Plate

11. Needle Plate

12. Roller Presser Foot

13. Thread Guide (Needle Bar)

14. Needle Bar

15. Thread Guide (Needle Bar Bushing)

16. Presser Bar

17. Face Plate

18. Thread Tension Regulator

19. Thread Guide

20. Thread Take-Up Lever Guard

21. Presser Regulating Thumb Screw

22. Thread Take-Up Lever

23. Thread Retainer

24. Oil Reservoir (Left)

25. Pre-Tension Device

3. Installation Preparation

3.1 Machine Installation Location

• Install on a flat, level floor

• Ensures smooth high-speed operation and prevents vibration

3.2 Mounting the Machine Head

1. Attach hinges to the back of the machine bed using supplied screws

2. Hook the hinges onto the table hinge plate

3. Set the machine head onto the table

3.3 Motor Installation

• Mount motor using supplied bolts, nuts, and washers

• Align motor pulley with balance wheel groove

• Install belt correctly

• Connect power supply and motor cord

3.4 Foot Pedal and Motor Lever

• Recommended pedal angle: 30–40°

• Incorrect angle increases operator fatigue

• Adjust connecting rod length if necessary

3.5 Bobbin Winder Installation

1. Position bobbin winder parallel to belt hole

2. Push lever into operating position

3. Align pulley with belt

4. Secure using two screws

3.6 Knee Lifter Installation

• Provides hands-free presser foot lifting

Installation Steps

1. Drill mounting hole under table per diagram

2. Install shaft bracket with spring hole facing operator

3. Install knee lifter shaft components in order:

   • Position bracket

   • Regulating rod bracket

   • Knee plate bar bracket

   • Spring

4. Secure shaft and tighten all screws

Adjustment

• Position bracket stopper must contact shaft bracket underside

• Adjust regulating rod so bell crank contacts correctly when presser foot is lowered

4. Oil Pan & Vibration Prevention

4.1 Oil Pan Installation

• Fit oil pan into table hole

• Ensure it does not interfere with knee lifter

4.2 Vibration Preventing Rubber

• Hollow four table corners: 20 mm radius, 13 mm depth

• Install rubber insulators securely

• Smooth hollowed surfaces before mounting

5. Preparation for Operation

5.1 Thread Selection

• Use high-quality sewing thread

• Upper thread must be left-twist

Twist Test:Twist thread toward yourself:

• Loosens → Right-twist

• Tightens → Left-twist

6. Needle Installation

Recommended Needle

• DP×5 (135×5)

Single Needle Installation

1. Raise presser foot

2. Turn balance wheel to raise needle bar fully

3. Move roller foot left

4. Loosen needle clamp screw

5. Insert needle with long groove facing left

6. Tighten screw securely

Double Needle Installation

• Insert needles with long grooves facing each other

• Push fully into needle clamp

• Tighten clamp screw securely

⚠️ For nylon or silk thread, slight needle angle adjustment may be required to prevent skipped stitches.

7. Upper Threading

Single Needle Threading Order

1. Spool Pin

2. Pre-Tension

3. Thread Retainer

4. Tension Discs (Right → Left)

5. Take-Up Spring

6. Thread Guide (Arm)

7. Take-Up Lever

8. Thread Guide (Arm)

9. Needle Bar Bushing Guide

10. Needle Bar Guide

11. Needle (Left → Right)

Double Needle Threading

• Left and right threads follow separate paths

• Thread needles from inside to outside

• Upper and lower take-up lever holes must match thread side

8. Bobbin Winding & Installation

Bobbin Winding

1. Thread through guide and tension discs

2. Wind thread 5–6 times onto bobbin

3. Insert bobbin with thread winding from underside

4. Engage bobbin winder pulley

5. Operate machine

6. Winder disengages automatically when full

Bobbin Winding Adjustment

• Adjust thread guide for even winding

• Adjust tension nut to reduce over-tight winding

• Ideal fill: 80% of bobbin capacity

Bobbin Installation

• Insert bobbin into hook

• Thread through hook slit and under tension spring

• Hold upper thread and rotate balance wheel once to pull up bobbin thread

9. Sewing Operation

Starting to Sew

1. Raise presser foot

2. Move roller foot back

3. Place material under needle

4. Hand-turn balance wheel to pierce fabric

5. Lower presser foot

6. Start sewing

⚠️ Leave 10 cm of thread tail when starting

Finishing

1. Stop with take-up lever at highest position

2. Raise presser foot

3. Pull fabric diagonally left

4. Cut threads, leaving 10 cm tail

10. Stitch & Tension Adjustment

Stitch Length

• Adjust using stitch regulating dial (mm scale)

Reverse Stitching

• Press reverse lever downward during sewing

Thread Tension Adjustment

Upper Thread

• Turn tension nut:

  • Right → Stronger

  • Left → Weaker

Take-Up Spring

• Standard materials: ~25 g

• Heavy materials: ~30 g

Operating Range

• Standard: 8 mm

• Light materials: Slightly more

• Heavy materials: Slightly less

Lower Thread

• Rarely needs adjustment

• Turn hook tension screw:

  • Right → Tighten

  • Left → Loosen

11. Feed Dog & Presser Adjustment

Feed Dog Height

• Light materials: 0.8 mm

• General: 1.0 mm

• Heavy: 1.2 mm

Presser Pressure

• Turn thumb screw right to increase pressure

• Turn left to decrease

12. Hook & Timing Adjustment

Needle and Hook Timing

• Needle raised 2.0 mm from lowest position

• Hook tip aligned with needle center

• Gap: 0.05 mm

• Hook tip below needle eye by 1.6 mm

Includes:

• Needle bar height adjustment

• Hook shaft alignment

• Opener clearance (~0.2 mm)

13. Cleaning & Lubrication

Cleaning

• Clean feed dog, hook, tension discs regularly

Lubrication

• Normal use: 2–3 times/week

• Continuous use: Daily

Oil Amounts

• Large oil points: ~5 cc

• Medium: 5–6 drops

• Small: 1–2 drops

⚠️ Ensure oil wick is fully saturated before operation

Greasing

• 
  

  Periodically grease gear box and hook shaft gears