Why Does My Sewing Machine Sew In Zig-Zags? (Solved)

Zig-zag stitches and bunching threads can often discourage new sewers.

Why is your machine doing this? There are several reasons this could be happening, from incorrect tension to threading issues.

Many of these are common problems with simple solutions:

Here’s Why Your Sewing Machine sews in Zig-Zags:

Your sewing machine is sewing in zig-zags most likely due to improper tension, threading, issues with your needle, maintenance requirements, poor thread quality or amateur repairs. Taking your machine to a professional or reading the manual can help.

1. Incorrect Tension

When a machine’s tension is set wrong, it can cause zig-zags, looping, and tight threads.

Each machine is different, and it’s always a good practice to check your manual first. (See the next section for tips on finding your manual online).

Here are a few places on your machine to check for tension issues.

Upper Thread Tension:

If your thread pulls tight underneath your fabric, this is a sign your upper thread needs its tension adjusted.

You can fix this by making sure your machine is threaded and set up correctly. If that doesn’t work, you can also try adjusting the tension dial on the side.

It would be best if you placed it between 4-5 for most projects.

Bobbin Tension:

Is the thread on top of your fabric too tight or loose?

This is a sign your bobbin case needs tension adjusting. This will require a screwdriver but is still an easy fix.

The tension can be adjusted by either loosening or tightening the small screw on your bobbin case. Afterward, the thread should slide through the case easily at a medium speed.

Incorrect Tension for the Fabric:

Some lightweight fabrics- silk, chiffon, or linen- may bunch or skip due to the thinner material.

In this case, you’ll probably need to loosen the tension and move to a larger stitch size.

2. Improper Threading

Threading your machine incorrectly can cause many problems, including uneven and crooked stitches.

Once again, check your manual for instructions. Or, if you prefer, try searching the internet for videos or step-by-step tutorials on threading your machine.

Here are a few places to check for improper threading:


Is it going in the right direction?

Are you missing any steps? (Threading steps are often marked on the machine itself.)

Is the thread going through the needle properly?


Is it in the case correctly? Is it threaded to the upper side? Is it wound tightly and neatly?


Is it still straight and sharp? Does it need cleaning of any kind?

Even when you think you know how to thread your machine, it can easily miss a single important step.

Especially make sure to read the manual if you get a new machine, even if it’s the same brand as your old one.

3. Needle Issues

Your thread and tension may be correct, but sometimes the needle itself is causing the problems.

Check these three things before starting any project:

  1. Is the needle on the right way?
    • If it’s put in backward, this can cause many issues. Make sure it’s facing the right way.
  2. Is it crooked?
    • If your needle is crooked or breaks, replace it right away.
    • It will only harm your machine and might even harm you.
  3. Is it sharp?
    • A dull needle can also cause many problems and should be replaced.

4. Irregular Maintenance

Also, consider giving your machine a cleaning to prevent any issues or damage.

Doing a monthly cleaning, especially if you use your machine frequently, is always a good idea.

You can wipe down most of it at home. Use a cloth to wipe off the dust and canned air or a small brush to get into smaller areas.

It would be best to keep your machine well oiled with sewing machine oil so everything works smoothly.

Always check with your manual for care instructions before cleaning. Many sewing stores can do this if your machine needs deeper cleaning.

5. Poor Thread Quality

Finally, a bad thread can cause skipping or breaking stitches.

While it might be tempting to use that box of thread from your grandmother, buying new, a good quality thread is probably better.

Check over your current thread collection and see if they are old or fraying.

Do they feel smooth or fuzzy? That fuzzy feel can indicate it will cause more lint and clog your machine, which leads to poor stitch quality.

It’s better to replace old threads than keep them and cause later issues.

Finding Your Machine Manual:

Your machine’s owner’s manual can tell you how to do most of these things on your specific machine.

If you don’t have the manual, most are available for download online.

You can search for your machine’s brand+model+manual, and you’ll find it almost every time.

Why is my Straight Stitch Still Zig-Zag?

If your straight stitch is zig-zagging, begin by going through the above list. Check the tension, thread quality, and needle. Double-check, none of the parts needs cleaning or replacing.

Use a scrap of cloth to test your stitches as you work, preferably the same type of cloth you’ll be using for the project. You can also use a piece of paper if you have no scrap fabric on hand.

It’s important to use the correct thread and tension for the fabric you’re sewing with. Even if your settings are fine, some fabrics need different tensions or stitch lengths. You can also search the internet for help on which tension and stitch types are best for your fabric.

Going to the Professionals:

If all else fails, try taking it to a repairman. They’re trained to find issues you may not be able to.

There may be a broken or stuck part you don’t know about.

Repair people see problems like yours all the time. They can easily spot what the issue might be and fix it when it takes you to find the solution on the internet.

You don’t want to try to repair it yourself and break your machine. Going to a professional is always best.

Can sewing machines get stuck in zig-zag mode?

Sometimes sewing machines can get stuck in zig-zag stitch mode. Here are a few things to try if this happens:

Go to the widest zig-zag and then back to the straight stitch. Sometimes parts can get stuck, which can jolt them back into place. Do it gently to prevent further damage.

Make sure you’re using the correct sewing plate. A sewing machine plate is the metal piece under your machine’s foot that guides the needle.

There are different sewing plates for zig-zag and straight stitches, which will make it difficult to sew the other.

Oil your machine. It may be something is sticking and preventing it from sewing straight. Check your manual for care instructions before oiling any parts.

Final Thoughts

Don’t let these common problems prevent you from sewing.

While having your machine sew crooked is frustrating, it’s often an easy fix. Go through these steps, and you’ll be back on track.

Every fabric and machine is unique, and it takes time to learn the best settings for yours. Consider making a cheat sheet to help you remember the best settings for each fabric.

Over time, you’ll become a pro at spotting and fixing easy problems like these.


Dealing With Common Thread Tension Issues

7 Easy Ways to Fix Stitch Quality Problems

Understanding Thread Tension in Your Sewing Machine