Overlock machines — Juki MO-654DE (two units)
Both units away for service since 10 October 2026 (together with the CoverPro). Ask in #textilrummet before planning to use them.
Two identical overlockers (sergers) — trim the edge and wrap it in thread as they sew. 2-, 3- and 4-thread overlock, rolled hems, flatlock. One is usually threaded white, the other black.
Juki MO-654DE
Location | |
Access | Free use, first come first served, no logging |
Needles | 130/705 H, flat side back (JL×2 in the left position for heavy fabric) |
Help / faults | Slack #textilrummet |
No bobbin, no straight stitch, zippers or buttonholes — use a sewing machine for those, and the CoverPro for coverstitch hems.
Safety
Fingers clear of the needles and the knife. The knife cuts permanently — test the trim position on scrap.
Remove pins before they reach the knife. No metal hardware.
Switch off for threading and adjustments; unplug for cleaning.
Looper cover and cloth plate closed before running.
Don't force a jam or pull fabric out against the needles.
Threading
Switch off. Extend the thread mast, open the looper cover and cloth plate, raise the needles (wheel towards you), disengage the upper knife (p. 8). Pull each thread firmly into its tension disc.
Order matters:
Blue — upper looper (p. 13). Leave 100 mm under the foot to the back.
Red — lower looper (p. 14). Needles up, press the lower-looper threading lever down, thread the device, turn the wheel towards you until the loopers just cross, then thread the eye.
Green — right needle (p. 15).
Yellow — left needle (p. 16).
Put the upper knife back down and close both covers. Ignore the page marked "MO-644D only".
Lower-looper thread broke? Unthread both needles, rethread the lower looper, then rethread the needles.
Check the upper-looper thread guide (around the moving rod) is there before threading. Missing → report; don't swap parts between the machines.
How to use
Pick the white or black unit. Power off: check needles and threading. Turn the wheel by hand.
4-thread overlock: both needles, both loopers, no converter, width selector at the rear red mark. Length 2.5, differential N, all tensions 4.
Upper knife down. Scrap under the foot, sew slowly. Guide — don't push or pull.
Check both sides: looper threads should meet at the edge. Change one setting at a time.
Sew off the fabric to make a 50–60 mm chain, cut it on the foot shank cutter.
Secure the chain ends, switch off, brush out lint.
Securing chain ends: knot or weave back with a darning needle — or start with a 30–40 mm chain, sew 2–3 stitches, needle down, foot up, bring the chain in from the left under the foot, and sew over it.
Stitch setups
Setup | Threads | Preparation |
|---|---|---|
4-thread overlock | Both needles + both loopers | No converter |
3-thread narrow (4 mm) | Right needle + both loopers | Remove left needle |
3-thread wide (6 mm) | Left needle + both loopers | Remove right needle |
2-thread overcast | One needle + lower looper | 2/3-thread converter |
3-thread super-stretch | Both needles + lower looper | Converter |
Converter: remove the upper-looper thread, fit the converter on the upper-looper shaft with its wire in the looper eye, route the lower-looper thread over the wire (p. 18). Remove it afterwards.
Quick-reference chart: use only the MO-654DE columns.
Rolled hem
Power off, needles up. Remove the left needle; keep right needle and both loopers; no converter.
Lower knife dial 1–2, width selector forward to the front red mark, length 1–1.5.
#80 spun thread: right needle 4–6, upper looper 3–5, lower looper 7–9. Other threads: p. 23 (woolly nylon in the upper looper only).
Afterwards: selector back to the rear mark, refit the needle, normal settings.
Adjustments
Differential (0.7–2.0): N normal; 1.5–2 for wavy stretch or gathering; towards 0.7 for puckering (p. 25). Gathering a light layer: length 4, differential 1.5–2.
Cutting width: power off, press the release and turn the knob (p. 8). Edge curls in → smaller; loops hang off the edge → larger.
Foot pressure: normally cap level with the cover top; more for heavy, less for very light (p. 10).
Troubleshooting
Problem | Check |
|---|---|
No chain / looper thread breaks | Threading order, every guide and disc, lower-looper device returned; rethread needles after the lower looper. |
Skipped stitches, needle breaks | Fresh needles, flat side back, fully up; screws tight; don't pull the fabric. |
Needle-thread loops underneath | Thread in disc and take-up guide; then tension (pp. 20–21). |
Loops beyond edge / edge curls | Cutting width; check selector position. |
Wavy or gathered seam | Differential and foot pressure. |
Won't feed, knife struggles | Foot down, lint, no hardware, stack not too thick. |
Noise, sparks, electrical | Unplug and report. |
After a thread break, overlap the old seam by 20–30 mm. More: manual p. 31.
Maintenance
Unplug, open the covers, brush lint from loopers, feed dogs and knives regularly.
Oil sparingly, only at the two points on p. 30. Wipe excess, test on scrap.
Lower knife replacement: p. 29. Upper knife, timing, tension calibration, electrical: service technician.
Specifications
Model | Juki MO-654DE (×2) |
Threads | 2, 3 or 4 |
Needles | 130/705 H (JL×2 left, heavy fabric) |
Stitch width | 6 mm (left needle), 4 mm (right), 2 mm (rolled hem) |
Stitch length | 1–4 mm |
Differential | 0.7–2.0 |
Max speed | 1,500 stitches/min |
Upper-looper thread guide | A2521-513-0A0 (parts book ref. 55, p. 8) |
Documents and links
MO-644D / MO-654DE manual (PDF) — printed page numbers above.
MO-654DE service supplement (PDF) — technicians.
Juki: instruction video · manual archive