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Cylinder Bed Overlock Machine (AZF8400 Series)

Yamato’s AZF8400 series cylinder bed overlock machine comes with a variable top feeder. Sewing tabular garment is smooth as there is no obstruction at all under and rear of cylinder bed. Combined with the RS25 device, it promises stable quality in the production of cuffs, neck and waist of T-shirts or sweat shirts – especially suitable for attaching collars.


  • Full speed operation for any process – need no reduction of sewing speed even in top gathering or sewing heavy weight material
  • Small cylinder bed (circumference: 151.5mm)
  • Stitch length can be changed via a push button
  • Adjustable differential feed amount via a lever
  • Movement of top feeder can be correctly adjusted by Micro Adjuster
  • Top feeder is designed to draw complete ellipse just as bottom feeder does with Yamato’s unique direct drive mechanism
  • No scratch by feed dog on thin and delicate material

Yamato RS25 – Coupled with this device, operators can attach collars to T-shirts or sweat shirts easily

  • Allows you to eliminate burst of seam as fabric holder guides fabric firmly
  • Attaches collar (waistband) in uniform width, thanks to holder which folds them correctly in half
  • Finish band flatly, which enhances appearance and quality of garments

AZF8403 or AZF8420 can attach small tubular bands to cuffs or ankles on the cylinder bed by swinging out the RS25 device

SKU: AZF8420 Categories: , Tag:


Information on production (example) (allowance rate: 20%)

Production Line
No. 1 No. 2 No. 3
Conventional collar attaching operation 32 sec.(900 pcs / 8hrs) 44 sec(655 pcs / 8hrs) 39sec(738 pcs / 8hrs)
Yamato AZF8403/K2/RS25 28 sec(1029 pcs / 8hrs) 32 sec(900 pcs / 8hrs) 35 sec(823 pcs / 8hrs)
Time Saved 4 sec 12 sec 4 sec
Productivity 114% (+129 pcs) 137% (+245 pcs) 112% (+85 pcs)


Simple mechanism without electronics to open and close holder (patent pending). RS25 includes air-operated holder (A) & (B), air-operated presser foot lifter (C), air-kit (D) for thread chain trimmer <K2>, and dust collector (E):

RS25 mechanism

Numbering on the Model
When customising your machine, make sure you quote rightly the model number with all the specifications you seek when inquiring about your machine. Refer to the list of specifications below:
AZF numbering

  1. Symbol of series
  2. Class number
  3. Sub model
  4. Needle distance (spacing between needles)
    0 = 1 needle, X = 2.0mm, Y = 2.4mm
  5. Overlock width
    Overlock width: indicated no. = ±0.5 (4=3.5 ~ 4.5mm)
  6. Feeding mode
    D = both positive and negative differential available
  7. Shape of knife
    F = flat knife, A = angled knife
  8. Additional devices:
    K2: automatic thread chain trimmer (vertical type . direct drive)
  9. Labour-saving device for attaching collar (completekit)


Model AZF8403 AZF8420
No. of Needles 1 2
Needle Type DCx27(#9 ~ #14) DCx27(#9 ~ #14)
No. of Threads 3 4
Use 1 needle, general seaming 2 needle, general seaming
Sewing Speed 6500 r.p.m



AZF8400 Class
Stitch Length 1.0 – 3.2mm
Presser Foot Lift 7.00mm (max)
Differential Feed Ratio 1:2.3 – 1:0.8
Top Feeder Life Amount 5.0 – 8.0mm
Needle Stroke 27.1mm


RS25 Device
Min. Max.
Circumference of garments 400mm 1050mm
Differential Feed Ratio 20mm 65mm


Our Recommendable Combinations

AZF8403/K2 or AZF8420/K2 AZF8403/K2 is recommendable for garments which need top covering operation in the following processes
Clutch motor or Needle positioner motor WIth needle positioner motor, needles can be rested at the upper dead point so that collar can be set on the right side of needle drop part