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Pfaff 591 Series: Troubleshooting Common Issues
Quick answer: Most common issues on the Pfaff 591 series, such as skipped stitches or thread breakage, are often resolved by checking the needle, thread path, tension settings, and the rotary hook. Regular cleaning and proper lubrication are also crucial for optimal performance.
The Pfaff 591 series industrial sewing machine is a workhorse, known for its reliability in heavy-duty applications. However, like any precision machinery, it can encounter issues that interrupt your workflow. This guide from 360 Digitizing Shop is designed to help operators quickly diagnose and fix the most common problems, getting your Pfaff 591 back to peak performance. We'll cover everything from skipped stitches to thread breakage, focusing on practical, actionable steps and the parts you might need.
Two-minute checks before you open anything
- Is the machine properly threaded (top and bobbin)?
- Is the needle inserted correctly, and is it the right type and size for your fabric and thread?
- Are the tension settings correct for your thread and fabric?
- Is the bobbin wound evenly and inserted correctly?
- Is there any lint or thread jammed in the rotary hook, feed dogs, or tension discs?
- Is the machine adequately lubricated?
1. Skipped Stitches or Poor Stitch Quality high likelihood
How to tell
You'll notice gaps in your stitch line, uneven stitches, or loose loops on the top or bottom of the fabric. The machine might sound different or struggle to form a consistent stitch.
Fix
- Ensure the correct needle type and size are used for your fabric and thread, and that it's inserted correctly and not bent or dull. Replace the needle if necessary.
- Re-thread the machine completely, making sure the thread is seated properly in all guides and tension discs.
- Check and adjust the upper thread tension. If stitches are loose on top, increase tension; if loose on the bottom, decrease tension.
- Inspect the bobbin and bobbin case for proper winding, insertion, and tension. Ensure there are no burrs or damage.
- Clean the rotary hook area thoroughly, removing any lint or thread buildup. Inspect the rotary hook for damage or wear. If damaged, it may need replacement.
- Verify the needle bar height and rotary hook timing. This is an advanced adjustment and may require a technician if you're unsure.
A worn or damaged rotary hook is a common culprit. Consider replacing with a Fu chao SKRT592-R KRT-592 Rotary Hook, Desheng DSH-PF591 Rotary Hook 91-263490-91, KOBAN SKRT592V2R SKRT592V2-R 91-263495-91, or LEAGUE Koban SKRT592V2-S Original Rotary Hook.
Parts involved: Needles & needle bars → Thread path & tension → Rotary hooks & bobbin cases →
2. Frequent Thread Breakage high likelihood
How to tell
The thread snaps repeatedly during sewing, either the top thread or the bobbin thread.
Fix
- Check the quality and age of your thread. Old or poor-quality thread can break easily.
- Inspect the entire thread path (from spool to needle) for any burrs, rough spots, or sharp edges that could be snagging the thread. Smooth any rough spots or replace damaged guides.
- Ensure the thread tension is not too tight. Adjust both upper and bobbin tensions.
- Verify the needle is correctly inserted, not bent, dull, or too small for the thread. A needle with a burr can also cause breakage.
- Clean the rotary hook area. Lint or thread fragments can cause friction and lead to thread breaks. Check the rotary hook for any nicks or damage.
- Ensure the bobbin is wound evenly and correctly. An unevenly wound bobbin can cause inconsistent tension and breakage.
Damaged tension discs or a rough rotary hook can cause thread breaks. Consider replacing the rotary hook with a Fu chao SKRT592-R KRT-592 Rotary Hook, Desheng DSH-PF591 Rotary Hook 91-263490-91, KOBAN SKRT592V2R SKRT592V2-R 91-263495-91, or LEAGUE Koban SKRT592V2-S Original Rotary Hook. Check for worn Pfaff 91-013139-05 Tension Support Rods.
Parts involved: Thread path & tension → Needles & needle bars → Rotary hooks & bobbin cases →
Parts you may need for Pfaff
In stock, tested before dispatch, Buyer Protection on every order. Part types for this problem: Rotary hooks & bobbin cases, Needles & needle bars, Thread path & tension, Presser feet & sewing parts.
Flying Tiger HAX1 15x1 Sewing Machine Needles 100-Pack for Brother ...$ 13.99View part →
PFAFF 335H, 335, 335G Needle Plate, Feed Dog, Needle, Presser Foot,...$ 27.09View part →
Groz-Beckert B27 DCX27 81X1 FFG/SES Industrial Sewing Needles Nm 75...$ 37.49View part →
Groz-Beckert 134 DPX5 135X5 Industrial Sewing Needles 100-Pack for ...$ 39.29View part →
KRT470-R Rotary Hook for PFAFF 471-493, GOLDEN WHEEL 9910, 9920, 88...$ 33.99View part →
PFAFF 91-026746-04C Needle Plate & 91-026745-04C Feed Dog Set for 1...$ 36.09View part →All Pfaff parts → Rotary Hooks & Bobbin Cases → Needles & Needle Bars → Thread Path & Tension →
3. Machine Jamming or Bird's Nesting (Thread Tangles Under Fabric) medium likelihood
How to tell
A large mass of tangled thread forms under the fabric, often causing the machine to seize up or make loud noises.
Fix
- Immediately stop the machine. Carefully remove the fabric and cut away the tangled thread. Do not pull forcefully.
- Remove the needle plate, bobbin case, and rotary hook. Clean out all lint and thread debris thoroughly.
- Re-insert the bobbin case and bobbin, ensuring the bobbin thread is correctly routed and tensioned.
- Re-thread the top thread completely, making sure it's seated in all guides and tension discs.
- Check the needle for bends or dullness and replace if necessary. Ensure it's inserted correctly.
- Verify that the upper and lower thread tensions are balanced. Unbalanced tension is a primary cause of bird's nesting.
A faulty rotary hook or incorrect bobbin case tension can contribute to jamming. Consider a replacement rotary hook like the Fu chao SKRT592-R KRT-592 Rotary Hook or LEAGUE Koban SKRT592V2-S Original Rotary Hook.
Parts involved: Rotary hooks & bobbin cases → Thread path & tension → Needles & needle bars →
4. Uneven or Loose Stitches (Top or Bottom) medium likelihood
How to tell
Stitches appear loose, loopy, or uneven, either on the top surface of the fabric or on the underside.
Fix
- Check the upper thread tension dial. If loops are on top, increase upper tension. If loops are on the bottom, decrease upper tension.
- Ensure the thread is correctly seated in the tension discs. Sometimes lint or a misplaced thread can prevent proper tensioning.
- Inspect the bobbin case tension. This is usually adjusted with a small screw on the bobbin case. Adjust in small increments.
- Verify the thread path is clear and free of obstructions or burrs.
- Use good quality thread that is appropriate for your fabric and needle size.
Worn or damaged tension discs or Pfaff 91-013139-05 Tension Support Rods can affect tension consistency.
Parts involved: Thread path & tension →
5. Needle Breakage medium likelihood
How to tell
The needle snaps during sewing, sometimes with a loud crack.
Fix
- Ensure you are using the correct needle system (e.g., 134, 135x5) and size for your Pfaff 591 and the material being sewn.
- Check that the needle is inserted all the way up into the needle bar and correctly oriented (scarf facing the rotary hook).
- Avoid pulling or pushing the fabric forcefully while sewing, as this can bend or break the needle.
- Inspect the presser foot for any damage or misalignment that might be striking the needle.
- Verify the needle bar height and rotary hook timing. If these are off, the needle can hit the hook or needle plate. This is an advanced adjustment.
- Ensure the feed dogs are not set too high or too low for the fabric, which can cause undue stress on the needle.
A bent or damaged needle bar can cause consistent needle breakage. Check the presser foot for alignment.
Parts involved: Needles & needle bars → Presser feet & sewing parts →
6. Fabric Not Feeding Properly low likelihood
How to tell
The fabric doesn't move smoothly under the presser foot, resulting in inconsistent stitch length, bunched fabric, or the machine 'marking time'.
Fix
- Ensure the presser foot pressure is correctly adjusted for your fabric. Too little pressure can cause slippage, too much can impede feeding.
- Clean the feed dogs. Lint and debris can accumulate, reducing their grip on the fabric.
- Check the feed dog height. They should rise above the needle plate sufficiently to grip the fabric. Adjust if necessary (refer to your machine manual).
- Inspect the feed dogs for wear or damage. Worn feed dogs may need replacement.
- Ensure the stitch length setting is appropriate and not set to zero.
Worn feed dogs or an incorrect presser foot can hinder feeding. Consider an Edge Guide with Mounting Screws for Pfaff 591 & Post-Bed Sewing Machines if you need better fabric control.
Parts involved: Presser feet & sewing parts →
Maintenance schedule
| When | What to do | Why |
|---|---|---|
| Daily / Every 8 hours of operation | Clean the rotary hook, feed dogs, and needle plate area. | Prevents lint and thread buildup that can cause skipped stitches, thread breakage, and jamming. |
| Daily / Every 8 hours of operation | Lubricate all designated oiling points. | Ensures smooth operation, reduces friction and wear on moving parts, and prevents overheating. |
| Daily / Every 8 hours of operation | Replace the needle. | A sharp, undamaged needle prevents skipped stitches, thread breakage, and fabric damage. |
| Weekly / Bi-weekly | Thoroughly clean under the needle plate and around the feed dogs. | Removes deeper lint accumulation that can affect fabric feeding and stitch quality. |
| Monthly / Quarterly | Inspect and clean tension discs and thread guides. | Ensures consistent thread tension and prevents thread snagging. |
| Annually / Bi-annually | Professional servicing by a qualified technician. | For comprehensive inspection, timing adjustments, and replacement of worn internal components. |
Stop and call a technician if
- If you suspect a major mechanical issue, such as incorrect timing, a bent needle bar, or internal gear problems.
- If the machine is making grinding noises or seizing up, and basic troubleshooting doesn't resolve it.
- If electrical components are malfunctioning or the motor is acting erratically.
- If you've followed all troubleshooting steps and the problem persists.
Prevent it coming back
- Perform daily cleaning of the rotary hook, feed dogs, and tension areas to remove lint and thread debris.
- Lubricate all designated oiling points regularly with the manufacturer-recommended oil. Refer to your machine's manual for specific points and frequency.
- Use high-quality needles appropriate for your fabric and thread, and replace them frequently (e.g., every 8 hours of sewing or at the first sign of dullness/bending).
- Use good quality thread that is suitable for industrial machines and your specific application.
- Ensure proper thread tension for both top and bobbin threads to prevent issues like skipped stitches or bird's nesting.
- Avoid pulling or pushing fabric excessively while sewing; let the feed dogs do their job.
- Regularly inspect the machine for loose screws, worn parts, or any signs of damage.
Frequently asked questions
How often should I clean my Pfaff 591?
For optimal performance, clean your Pfaff 591 daily or after every 8-10 hours of operation, especially around the rotary hook and feed dog areas. A more thorough cleaning and lubrication should be done weekly or bi-weekly depending on usage.
What kind of oil should I use for my Pfaff 591?
Always refer to your Pfaff 591's instruction manual for the specific type of industrial sewing machine oil recommended by the manufacturer. Generally, a high-quality, non-staining, clear industrial sewing machine oil is used.
My Pfaff 591 is making a strange noise. What should I do?
Unusual noises often indicate a lack of lubrication, a loose part, or an obstruction. Stop the machine immediately. Check for thread jams, clean and oil the machine, and inspect for any loose screws or worn parts. If the noise persists, it's best to call a technician.
Can I use any bobbin in my Pfaff 591?
No, it's crucial to use bobbins specifically designed for your Pfaff 591 series machine. Using incorrect bobbins can lead to tension issues, thread jams, and damage to the bobbin case or rotary hook.
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