My overlocker was working well, but suddenly it now has loose stitches?

We are often asked...why is my overlocker tensions loose and very uneven? Last time it was stitching well, now the stitches are awful...it must be broken!? It keeps missing stitches, why will it not overlock? Its not my fault, the overlocker sews irregular stitches? What's going on?

These are likely the most frequently asked questions regarding overlocker issues.  Many people think there is an underlying problem with their machine, when more often than not, it is the user..!

A typical query would be 'it was working fine, now its not stitching, what can I be doing wrong?'

From 30 years experience troubleshooting and repairing overlockers, my first response to the user is to ask...'have you double checked the threading.' In the vast majority of cases, that is where the issue lies, as we will explain.

Have a close look at the two images below. Both overlockers have been threaded, just as the instruction book points out. Following the threading paths, through the correct loopers and needles. Now there is one simple and most important issue that has been overlooked...the thread is not lying between the thread tension discs!.

What will happen if the thread is not between the tension discs?
This will mean zero thread tension for that needle or looper. This is not the fault of the overlocker, it is more the users inability to thread it correctly. Here are some example images showing what the stitches will look like, when it all goes wrong.

In the image below, you can clearly see the thread has been laid loosely in position and has not been pulled taut and into the tension unit.

As a last check just before starting to overlock,  a good habit to get into would be to have a quick, close up look at the tensions. Look for the tell-tail sign that you can actually see in the image above, that the thread is laying on top of the tension discs. This means no thread tension! It will also mean, loose stitches, unbalanced overedge, fabric pulling, thread snapping or at worst, a bent needle.

This threading error can be double checked by lowering the presser foot and gently pulling the suspect thread from the rear of the needle, or looper eye. It should have some tension and you should feel a little resistance. If it has zero tension, it is not threaded correctly.

Look closely at this first image above and see how the blue thread runs through the tension dial. Notice how the thread has not been pulled taut whilst threading and is layed on top of the tension discs. This threading error can easily happen and can be quickly fixed.

The image below shows the correct threading. You can see how the thread is hidden between the tension discs and has been pulled deeper in to the tension unit. This is the view you should have when closely inspecting each tension dial, just prior to starting your stitching.