There’s nothing more frustrating than your serger acting up in the middle of a sewing project, and it can often be very difficult to find the source of these problems. More often than not, however, the problem lies with the lower looper of the serger; i.e. the part that loops the thread back and forth between the stitching line and the edge of the fabric on the underside of the fabric.  In this post, I discuss how to fix some of the most common lower looper problems.

Lower looper thread keeps breaking

Usually, incorrect threading is the cause of this problem.  Solve it by cutting ALL of the threads (yes, ALL, including the threads in the needles and the upper looper.  DO NOT just cut the thread in the lower looper), then running the machine to make sure the threads are clear of the stitch finger and there are no stray threads caught in the needle plate.  

Then, re-thread the entire machine in the order that your machine manual specifies.  For example, on my Brother 1034D serger, that means starting with the upper looper, then the lower looper, and then the needles. 

You should also make sure that the machine is threaded in the proper manner for your machine.  Always double check your manual to make sure you are threading the machine EXACTLY as shown, as sergers are very finicky and sensitive to even the smallest threading errors.  For example, on my Brother 1034D serger, it is very important for the lower looper thread to pass UNDER the upper looper thread, otherwise the lower looper thread will get caught on the upper looper thread and snap.  It is also very important to thread the lower looper thread so it goes towards the needles, not away to the outside of the lever as is shown in the diagram on the machine.

If you’ve re-threaded the machine and the thread is still breaking, try replacing the thread.  Sometimes thread can disintegrate over time, particularly if it has been sitting out in the sun.  Try switching out to a new thread cone to see if that solves the problem.

If that still doesn’t work, try replacing the needles with fresh, sharp ones, and make sure that they are sitting in the correct position in the thread bar (e.g., make sure they are pushed all the way to the top of the thread bar and the needles point straight down.  Note that the needles should NOT be even – one should be higher than the other).

If your problem continues, try looking for places where the thread might be getting caught:

• Double check that the thread is going through the clips and the tension dials properly (some sewists even try to ‘floss’ the tension dials to get lint out). 

• Reduce the tension to reduce the stress on the thread. 

• Check your thread spools to make sure that the thread isn’t getting caught on the spool as it comes off, and check that your thread bar is pulled up to the maximum height. 

• Check that the thread is going directly through the eye of your needle and is not wrapped around the needle.

• Check that the thread is not catching on the loopers. Sometimes, a needle can accidentally hit the loopers, creating a ‘burr’ on the looper that then catches the thread.  If this happens, take your machine in to be serviced – don’t try to fix this yourself.  Another place that the thread might be getting caught in the Brother 1034D serger is the threading lever that feeds the thread into the lower looper.  The ‘hook’ on that threading lever has been known to catch threads.  The key is not to pull the thread all the way to the right of the hook on the lever (if that doesn’t make sense, check out this video for an illustration of the right and wrong way to thread that part of the machine).

• Clean out any lint that might have built up in your machine using the tiny brush that comes with your serger and one of those cans of compressed air that are typically used to clean computer keyboards.  The lint built up inside the machine can cause things to break and catch the threads.  If you haven’t cleaned your machine for awhile, try removing the needle plate so you can get in and remove the lint buildup there.

Lower looper thread keeps unthreading

This problem is very similar to the problem above and can be solved using the same methods suggested above – first check the threading, then try changing the needle and thread, and finally look for places where the thread might be catching.

Serger needle is hitting the lower looper

If you hear clicking sounds when you serge, you could be having an issue where the needles of the serger are hitting the lower looper.  This problem is caused by the serger needles and/or the lower looper being out of alignment, which then causes them to hit each other.

The easiest fix for this problem is to check that your needles are properly positioned in the needle bar.  Make sure that the needles are pushed up until the needle bar as much as possible, and that the needles are pointing straight down.  Also check that you are using the right size needles for your serger – a needle that is too large might hit the lower looper.

If that doesn’t fix the issue, then the problem probably lies with either the position of the lower looper, or the timing of the lower looper vis-à-vis the needles and the upper looper.  However, re-positioning the lower looper and changing the timing of the loopers is a complex task that should ideally be left to the professionals.  However, if you’re cost conscious and would rather attempt to fix it yourself, try following the instructions in this blog post to reposition the looper. If you think that it is a timing issue, try watching this video to learn how to fix it.  You’ll need a screwdriver and an Allen wrench, and a lot of patience to fiddle with machine parts, because it is difficult to get the positioning right (the exact positions vary from machine to machine, and the gauges that professionals use to get the positioning right are not available to us ordinary folks).

Lower looper thread is pulling to the right side of the fabric

Another common problem with the lower looper is that the tension could be off for your stitch and your fabric.  You can tell if this is the problem by looking at your stitch – if the lower looper thread looks like it is being pulled onto the other side of the fabric (rather than ending at the edge of the fabric), then the tension on your lower looper is too loose. 

To fix this, try increasing the tension incrementally and stitching a small sample each time, until you get a balanced stitch. In a balanced stitch, the upper and lower looper threads should extend to the edge (and no further), as shown in the examples below.

Lower looper thread is too tight and pulling the upper looper thread to the wrong side of the fabric

The converse of the problem above is when the lower looper thread is too tight and it pulls the upper looper thread into the wrong side of the fabric.  When this is the case, you will typically find that the lower looper thread causes ‘tunneling’ in the fabric. 

To fix this, incrementally loosen the tension and stitch a small sample each time until you get a balanced stitch.

What other problems have you experienced with the lower looper of your serger? How have you fixed those problems? Let me know in the comments!