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Juki DDL-8700 Series: Common Problems & Fixes
Quick answer: Most Juki DDL-8700 problems like skipped stitches, thread breaking, or needle breaking are often resolved by replacing the needle, rethreading the machine, cleaning the bobbin area, or adjusting tension. More complex issues may involve the rotary hook or motor.
The Juki DDL-8700 series is a workhorse in the industrial sewing world, known for its reliability and speed. However, like all machinery, it can encounter issues. This guide provides common problems, how to identify them, and practical steps to get your machine back up and running, focusing on solutions you can implement yourself with readily available parts.
Two-minute checks before you open anything
- Is the machine plugged in and powered on?
- Is the needle inserted correctly and not bent or dull?
- Is the machine threaded correctly, both upper and bobbin?
- Is the bobbin wound evenly and inserted properly?
- Are there any visible thread jams or lint buildup in the bobbin case or under the needle plate?
- Is the presser foot lowered?
1. Skipped Stitches or Poor Stitch Quality high likelihood
How to tell
Stitches are inconsistent, form loops on the fabric (especially underneath), or appear loose and uneven. The machine may sound different during stitching.
Fix
- Replace the needle with a new, correct size and type. Ensure it's inserted correctly, flat side facing the back.
- Completely rethread the machine, ensuring the thread is seated properly in all guides and tension discs.
- Clean the bobbin case and rotary hook area thoroughly. Remove any lint, dust, or thread scraps.
- Check and adjust the upper thread tension. Start with a medium setting and adjust as needed.
- Verify the bobbin is wound evenly and inserted correctly into the bobbin case.
- Inspect the rotary hook for burrs or damage. If damaged, it may need replacement or professional servicing.
A fresh Groz-Beckert 134 DPX5 135X5 Industrial Sewing Needles 100-Pack or Groz-Beckert DBX1 16×257 DB*1 Industrial Sewing Needles can often solve this. If the rotary hook is damaged, consider a Rotary Hook HSH-7.94B HSH-7.94A B1830-127-OAO or Hirose HSH-7.94BTR Rotary Hook.
Parts involved: Needles & needle bars → Rotary hooks & bobbin cases → Thread path & tension →
2. Thread Breaking (Upper or Lower) high likelihood
How to tell
The thread snaps frequently during sewing, either the top thread or the bobbin thread.
Fix
- Replace the needle. A bent, dull, or incorrect needle is a common cause.
- Check the entire thread path for snags, burrs, or obstructions, including the thread guides, tension discs, and take-up lever.
- Ensure the thread is good quality and suitable for the fabric and needle size.
- Clean the tension discs. Lint can get trapped and cause uneven tension, leading to breaks.
- Inspect the rotary hook and bobbin case for burrs or sharp edges that could fray the thread.
- Adjust thread tension. Too much tension can cause thread to snap.
Always start with a new needle, such as Groz-Beckert DBX1 16×257 DB*1 Industrial Sewing Machine Needles. If the rotary hook is the issue, a replacement like HSH-7.94B Rotary Hook B1830-127-OAO may be needed.
Parts involved: Needles & needle bars → Thread path & tension → Rotary hooks & bobbin cases →
Parts you may need for Juki DDL-8700
In stock, tested before dispatch, Buyer Protection on every order. Part types for this problem: Needles & needle bars, Rotary hooks & bobbin cases, Thread path & tension, Presser feet & sewing parts.
Industrial Sewing Machine Zipper Presser Foot S518N - Compatible wi...$ 8.49View part →
Rotary Hook HSH-7.94B HSH-7.94A B1830-127-OAO for JUKI DDL-5550 DDL...$ 16.49View part →
Industrial Curved Hemming Foot for Juki DDL-8700, Brother DB2-B755,...$ 13.29View part →HSH-7.94B Rotary Hook B1830-127-OAO for JUKI DDL-5550 DDL-8500 DDL-...$ 16.49View part →
Groz-Beckert 134 DPX5 135X5 Industrial Sewing Needles 100-Pack for ...$ 39.29View part →
Groz-Beckert DBX1 16x257 DB*1 Industrial Sewing Needles for JUKI DD...$ 10.49View part →All Juki DDL-8700 parts → Needles & Needle Bars → Rotary Hooks & Bobbin Cases → Thread Path & Tension →
3. Needle Breaking medium likelihood
How to tell
The needle snaps during sewing, often with a loud crack. This can happen repeatedly.
Fix
- Ensure the correct needle type and size are used for the fabric and thread. (e.g., Groz-Beckert 134 DPX5 135X5 or DBX1 16×257).
- Check that the needle is inserted correctly and fully into the needle bar, with the flat side facing the back.
- Verify the presser foot is appropriate for the task and securely attached. Ensure it's not hitting the needle.
- Inspect the needle plate hole for damage or burrs that could deflect the needle.
- Check the rotary hook timing. If the hook is hitting the needle, timing adjustment is needed (professional service recommended).
- Avoid pulling or pushing the fabric aggressively while sewing, as this can bend and break the needle.
Using the correct Groz-Beckert Industrial Sewing Needles is crucial. Ensure your Industrial Sewing Machine Zipper Presser Foot S518N or Industrial Curved Hemming Foot is not misaligned.
Parts involved: Needles & needle bars → Presser feet & sewing parts → Rotary hooks & bobbin cases →
4. Machine Not Sewing / Jammed medium likelihood
How to tell
The handwheel is difficult to turn, the machine makes a grinding noise, or it simply won't start sewing despite power being on.
Fix
- Turn off the machine and unplug it. Remove the needle, presser foot, and bobbin case.
- Carefully remove any tangled thread from the bobbin area, under the needle plate, and around the rotary hook.
- Check for any foreign objects (pins, fabric scraps) that might be jamming the mechanism.
- If the machine is still stiff, check the Juki Lower Gear & Pinion Set for damage or obstructions.
- Ensure the machine is properly lubricated according to the manufacturer's manual. Lack of oil can cause seizing.
A jammed rotary hook (e.g., HSH-7.94B Rotary Hook B1830-127-OAO) is a common cause. Inspect the Juki Lower Gear & Pinion Set for damage.
Parts involved: Rotary hooks & bobbin cases → Belts, pulleys & gears → Lubrication & maintenance → Head & mechanical parts →
5. Motor or Electronic Control Issues low likelihood
How to tell
Machine doesn't turn on, motor hums but doesn't run, inconsistent speed, or error codes appear on the control panel.
Fix
- Check all power connections, including the plug, power cord, and foot pedal connection.
- Ensure the machine's power switch is on.
- If the motor hums but doesn't turn, check for a mechanical jam (see 'Machine Not Sewing / Jammed').
- For inconsistent speed or no power, inspect the JUKI SC-920 Control Box PCB Assembly for visible damage or loose connections.
- If an error code appears, consult your machine's manual for specific troubleshooting steps related to that code.
- If the motor is completely unresponsive, the Zoje Huilong Electronic Lockstitch Motor or the Jack A4B 220V Mainboard Stepper Motor Controller might need professional diagnosis or replacement.
Issues could stem from the JUKI SC-920 Control Box PCB Assembly, Jack A4B 220V Mainboard Stepper Motor Controller, or the Zoje Huilong Electronic Lockstitch Motor. These are typically advanced repairs.
Parts involved: Motors & drivers → Circuit boards & electronics → Control panels & displays → Cables & wiring →
Maintenance schedule
| When | What to do | Why |
|---|---|---|
| Daily (or before each shift) | Clean the bobbin area, feed dogs, and needle plate. | Prevents lint buildup that can cause jams, skipped stitches, and thread breaks. |
| Daily (or before each shift) | Oil all designated lubrication points. | Ensures smooth operation, reduces friction and wear, and prevents seizing. |
| Weekly | Inspect and replace the needle. | Dull or bent needles cause skipped stitches, thread breaks, and fabric damage. |
| Monthly | Clean tension discs and thread guides. | Removes hidden lint that can cause inconsistent thread tension. |
| Quarterly | Check for loose screws and general wear on parts like the rotary hook and presser feet. | Proactive maintenance prevents major breakdowns and ensures stitch quality. |
Stop and call a technician if
- If you've followed all troubleshooting steps and the problem persists.
- If the machine requires complex mechanical adjustments, such as rotary hook timing or motor calibration.
- If you suspect a major electronic component failure (e.g., control box or mainboard).
- If you are uncomfortable performing any of the recommended fix steps.
Prevent it coming back
- Regularly clean the machine, especially the bobbin area, feed dogs, and tension discs, to prevent lint buildup.
- Oil the machine daily or before each use, following the manufacturer's lubrication points and schedule.
- Always use high-quality needles and thread appropriate for your fabric and project.
- Replace needles frequently (e.g., after 8 hours of continuous sewing or at the start of a new project) to prevent dullness or bending.
- Perform routine checks for loose screws, worn parts, or unusual noises.
- Avoid pulling or pushing fabric excessively, allowing the feed dogs to do their job.
Frequently asked questions
Why is my Juki DDL-8700 making a loud noise?
Loud noises often indicate a lack of lubrication, a mechanical jam (check the bobbin area and under the needle plate), or a worn/damaged part like the rotary hook or gears. Stop sewing immediately and investigate.
How often should I oil my Juki DDL-8700?
For industrial machines like the DDL-8700, daily oiling is recommended if used continuously. For intermittent use, oil before each use or every few days. Always refer to your specific machine's manual for exact lubrication points and frequency.
What type of needles should I use for my Juki DDL-8700?
The Juki DDL-8700 typically uses DBx1 (also known as 16x257) or 134 (DPx5) industrial sewing machine needles. Always match the needle size to your thread and fabric type. We stock Groz-Beckert DBX1 16×257 DB*1 Industrial Sewing Needles and Groz-Beckert 134 DPX5 135X5 Industrial Sewing Needles.
My Juki DDL-8700 isn't picking up the bobbin thread. What's wrong?
This is usually caused by an incorrectly inserted needle, incorrect needle size, improper upper threading, or issues with the bobbin case or rotary hook. Replace the needle, rethread the machine, and check the bobbin area for lint or damage.
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