Why Does My Sewing Machine Keep Jamming?
Having your sewing machine suddenly jam in the middle of a project can be incredibly frustrating. One minute you’re happily sewing along, and the next your machine is making strange noises, tangling threads, or refusing to move at all. Sewing machine jams happen to every sewist at some point, but that doesn’t make them any less annoying when they ruin your sewing flow.
The good news is that many common sewing machine jam causes are easy to identify and fix yourself.
In this comprehensive guide, we’ll cover the top 14 reasons your sewing machine may be jamming and how to troubleshoot them. With a few simple cleaning, maintenance, and setting adjustments, you can get your machine running smoothly again in no time.
Top 14 Causes of Sewing Machine Jams
There are a number of things that can cause jams and malfunctions in sewing machines. Here are the most common culprits to check when your machine starts acting up:
1. Incorrect Threading
One of the most common causes of sewing machine jams and issues is incorrect threading. If the thread is not following the proper path from spool to needle, it can tangle, bunch, or break. Be sure to:
- Raise the presser foot before threading
- Follow the threading guide for your specific machine
- Pull thread through tension discs and thread guides
- Insert thread correctly from front to back of needle
If in doubt, completely rethread the machine from scratch.
2. Poor Tension Balance
The tension balance controls how the top and bottom threads interlock. If it’s off, stitches may be loose, tight, or unequal.
- Loose top tension causes looping on underside
- Tight top tension causes thread to break
- Adjust top tension according to fabric type
To check bobbin tension, hold thread tail and case – it should drop only 1″. Adjust bobbin screw if needed.
3. Lint and Dust Buildup
Lint and dust in the bobbin area or on moving parts can cause jams. Regular machine cleaning is essential.
- Use compressed air to blow out lint in hidden areas
- Gently brush out lint in bobbin case and feed dogs
- Wipe down with soft cloth to remove built-up dust
4. Incorrect Needle Size or Type
Using the wrong needle can cause skipped stitches, breakage, or damage.
- Check manual for recommended needle sizes for your fabric
- Use ballpoint for knits, sharp for wovens
- Change needle every 6-8 hours of sewing time
5. Failure to Leave Long Thread Tails
Not leaving 3-4″ thread tails when starting to sew can cause threads to pull out of needle or tangle.
6. Feed Dogs Not Raised
If feed dogs are lowered for darning or free motion quilting, fabrics won’t advance and machine may jam.
- Check if feed dog lever is in correct raised position
- Make sure presser foot isn’t pressing too heavily on fabric
7. Fabric Is Warped, Stretched, or Placed Incorrectly
Fabric that is stretched, warped, or bunched under the presser foot may cause jams.
- Use fabric stabilizer on very lightweight fabrics
- Check fabric grainlines before cutting and sewing
- Don’t pull or stretch fabric while sewing
8. Sewing Over Dense Layers or Heavy Seams
Asking your machine to sew over many dense layers or seams can overwhelm mechanisms.
- Check fabric layers – presser foot should easily pass over it
- Consider a heavy-duty machine for very thick fabrics
- Use an appropriate presser foot, like a jeans foot
9. Poor Quality Thread
Cheap or low quality thread can shed lint, tangle, or break easily, causing jams. Invest in good thread – it makes a difference!
10. Inserting Bobbin Incorrectly
If the bobbin is not inserted correctly into the bobbin case, sewing cannot happen smoothly.
- Refer to manual for how to insert bobbin properly
- Make sure it is fully inserted and locked into place
11. Damaged or Bent Needle
The needle is one of the most sensitive parts of the machine. A damaged or bent needle cannot pass smoothly through fabric.
- Replace needle at first sign of damage or dulling
- Make sure needle is inserted completely and correctly
- Do not pull fabric – let machine feed it naturally
12. Presser Foot Not Properly Attached
An improperly attached presser foot can allow fabric to shift around and cause jams.
- Check that correct shank size presser foot is attached
- Make sure presser foot is clicked or screwed tightly in place
13. Internal Issue or Part Malfunction
In some cases, there may be an internal problem with the machinery. Intermittent issues definitely warrant a trip to the repair shop.
14. Lack of Regular Maintenance
Sewing machines need regular cleaning and oiling to keep everything moving smoothly. Neglecting machine maintenance is asking for trouble.
- Clean lint and dust out regularly
- Oil moving parts every 3-5 hours of use
- Replace old needles, presser feet, etc.
By methodically checking each potential cause, you should be able to troubleshoot and fix most sewing machine jams yourself. But when in doubt, don’t force mechanisms that feel stuck – take it to a professional for service.
Sewing Machine Jam Troubleshooting Guide
Use this handy chart to troubleshoot common machine jam causes:
| Issue | Potential Causes | Solutions |
|---|---|---|
| Loose, looping stitches on underside | – Incorrect threading – Bobbin threaded incorrectly – Low top thread tension | – Rethread top and bobbin – Adjust top tension |
| Skipped stitches | – Needle inserted incorrectly – Bent or damaged needle – Lint in bobbin area | – Check needle and reinsert – Replace needle – Clean lint out |
| Fabric not feeding smoothly | – Feed dogs lowered – Improper presser foot pressure – Lint in feed dogs | – Raise feed dogs – Adjust presser foot pressure – Clean feed dogs |
| Thread bunching or shredding | – Poor quality thread – Incorrect needle size/type – Top tension too tight | – Use good quality thread – Change needle – Adjust top tension |
| Thread breaks | – Top tension too tight – Needle hits plate or hook – Not leaving long thread tails | – Loosen top tension – Adjust needle position – Leave 3-4″ thread tails |
| Machine jams/won’t sew | – Jammed with tangled thread – Internal part malfunction | – Clean out threads – Take for service |
FAQs About Sewing Machine Jams
Here are answers to some frequently asked questions about dealing with sewing machine jams:
What are common signs my machine is jammed?
- Machine stops sewing and makes a grinding noise
- Tangled mess of threads under fabric
- Needle hits plate or hook and won’t move
- Fabric bunches or won’t feed smoothly
Why does my thread keep shredding or breaking?
There are several reasons why a thread may keep shredding or breaking while sewing. Here are some possible causes
- Top tension is too tight
- Wrong size or type needle for fabric
- Poor quality, lint-shedding thread
- Not leaving long enough thread tails
How can I prevent my sewing machine from jamming?
- Clean lint and dust out regularly
- Oil moving parts every 3-5 hours
- Replace needles every 6-8 hours of sewing
- Use good quality thread
- Check tensions are balanced
Why does my fabric pucker or bunch up when sewing?
- Top thread tension too tight
- Incorrect needle/thread for fabric
- Don’t pull on fabric while sewing
What do I do if my fabric gets jammed in the machine?
- Turn handwheel toward you to raise needle
- Lift presser foot and remove any loose threads
- Carefully clip threads to loosen jammed fabric
- Pull fabric back and out of machine
How can I fix a jammed handwheel or mechanism?
- Turn handwheel toward you, not away
- Remove loose threads if visible
- Take machine to repair shop – don’t force stuck handwheel
Preventing Future Sewing Machine Jams
While occasional jams are bound to happen, you can prevent many issues by keeping your machine well-maintained and adjusted:
- Clean lint and dust out regularly, especially under the bobbin area and feed dogs
- Oil moving parts like the hook every 3-5 hours of sewing time
- Replace needles every 6-8 hours of sewing to keep them sharp
- Use quality thread and needles – cheap ones cause issues
- Check tensions are balanced for each new project
- Don’t pull on fabric while sewing – let the feed dogs advance it
- Check presser foot pressure is not too heavy for fabric
- Be gentle if clearing jams – don’t force mechanisms
- Take for servicing every year or so to address any issues
Following good sewing machine care practices will keep everything running smoothly for all your projects. And be sure to consult your machine’s manual if you’re ever unsure of proper threading, needle types, oiling points, etc. The specifics can vary by make and model.
Sewing Frustration Solved!
Sewing machine jams are incredibly annoying when you’re trying to complete a project, but they don’t have to completely derail your progress. Now that you know the most common reasons machines jam and how to troubleshoot them, you can get back to sewing in no time.
Be methodical in checking potential causes, adjust your machine settings, clean and oil regularly, and your machine should once again be a smooth sewing companion. Just be patient with the process and don’t force mechanisms while troubleshooting.
Do you have any other sewing machine jam fixing tips? Share your frustrations and solutions in the comments!