Stitches looping, how to reset the tensions on my overlocker after it goes wrong?

Getting your overlocker tensions set up correctly can be a dark art for most people. We hope that while you are following our guide, it will bring new light and understanding to your quest for perfect overlocker tensions.

Overlockers are well engineered and I love working on them. To me they are perfectly engineered and have not really changed an awful lot of the years. Once setup, if the user was going to continue to use the same thread brand, type and thickness, the overlocker can be left untouched for years and it will still could achieve perfect overedge stitching results.

What can go wrong if the tensions are not set correctly?

Thread snapping, skipped stitches, uneven stitches, looping or loose stitches, seam puckering and some of the issues caused by thread tension problems on overlockers.

Lets start with basics. Check we have all the correct settings ready to sew a simple 4 thread overlock stitch to adjust the tension settings. As a test sample use a plain cotton lightweight fabric.

• Set the differential feed to zero = both feed dogs moving together in perfect symmetry.
• Remove the narrow, rolled hem plate, or set your overlocker for general overlocking by moving the rolled hem lever out of working mode.
• We will only be using decent quality threads of the same brand, like Gutterman or Coats moon. We will not be using cheap hairy thread, that will twist and knot, as it comes off the cone.
• You must start by using new needles. Don't start fault-finding tension problems using bent needles!
• Lastly, make sure the thread cone is placed directly beneath the tension mast. Is the mast swung in the opposite position, so the first thread path is not in alignment, perfectly above the thread cone.

I will be using the popular Brother 2104d, 4-thread overlocker manufactured by Brother for this, how to reset tensions tutorial.

Use the below image as reference, it displays the colour tension dials and threading paths. I will use the same colour threads as the tension dials indicate from left to right;

• Tension 1 - Left needle thread -  Yellow 
• Tension 2 - Right needle thread -  Red 
• Tension 3 - Upper looper thread -  Green 
• Tension 4 - Lower looper thread -  Blue 

Our end result will be to achive the perfect 4-thread overlock stitch, just like this image.

Both the upper (red) and lower (blue) looper threads interlock correctly on the cleanley cut fabric edge. 

There is no pulling of puckering of the fabric as the needles (yellow and red threads) penetrate the fabric.

No loops, or excess thread on the loopers (green and blue) interlocked fabric edge, the balance is not too tight, nor too loose.

In stark contrast, the image below clearly shows the tensions are wrong, and starting to cause loose loops on the fabric edge. The upper looper green thread is too loose and is being pulled to the underside of the fabric. One could also say the blue thread may have too much tension, but it shows no sign of distorting the needle,  yellow or red threads. I would set the green thread to a lower tension setting.

Can you see how the blue lower looper thread is being pulled to the top side of the fabric. The green thread doesnt look taut, it looks relaxed. I would adjust the blue lower looper thread to a highter tension setting, to bring back the stitch tension and loopers balance.

Compare this image to the one above, see how the fabric is starting to pucker. Look at the red needle thread, it is pulled too straight and flat. The red and maybe the yellow needle threads, have too much tension, causing the fabric to pucker. Adjust the red needle tensions to a lower setting and sew another sample. You may also have to loosen the tension on the yellow, left needle thread also.

What happens if you dont have your overlocker threaded correctly. Lots of birds nest thread loops and a real tangle of overlay, loose thread loops, with stitches skipping. The most likely cause is miss-threading of the tension unit. This FAQ explains more about user threading errors. The image below shows user threading errors.