Tips For Threading An Overlocker!
Where would you start? There is a huge range of different overlockers available. There are many similarities between overlockers however each one is different to thread, particularly when it comes to threading the loopers.
I can give you some tips, apart from the obvious..."read the instruction book"... that old chestnut! The information below is based on the tensions being set to the default setting in the instruction book, numbered tensions, usually 3-4 would be a good starting point.
80% of overlock machines having stitching problems which is related to one thing; user threading.
19 % will be a jam up, may be the loopers have bashed in to each other or the needles; maybe one needle has slid down the wrong side of the needle shield. These issues can happen at any time, usually because the user is pulling the fabric though the machine with a little too much enthusiasm. Or maybe it hadn't been threaded correctly in the first place.
The other 1% or less will be a genuine fault, e.g, a metal needle bar link has snapped or motor belt snapped.
In general it would always be advisable to start threading the upper/right looper 1st. Secondly would be the lower/left looper. Then on to the needles from the inside/right and then to the outside/left needle which is last.
So here we go to fix 80% of overlocker threading problems... The instruction book will say "follow the coloured threading paths through the tensions". Mostly it is pretty easy to follow the coloured dots, but when it comes to the tension units... this is where more explanation is needed.
The thread tension on any overlocker consists of two polished discs about the size on a 10p located on a shaft through the centre. A fine spring pushes these two discs together giving tension to the thread. The thread MUST lay IN-BETWEEN these two discs and with the help of a spring, gives tension to the thread.
Warning #1: It is extremely easy for the thread to go; left or right of the discs, which equals no tension!
Warning #2: The thread must not rest on top edges of the tension discs, this will mean no thread tension!
Some overlockers have a tension release mechanism, which automatically opens the tension discs when the presser foot is lifted...a great feature to have. This means that any thread changes need to be done whilst the presser foot is up, then lower the foot when threading the needle eye. If you have just pulled your overlocker out from a cupboard where it has not been used for a while, one thing may need checking, that is if you are having problems with stitching! Because the thread tension discs are polished, they may stick together, hence causing the thread to rest on top of the
tension discs. The thread can not locate in-between the discs, which equals a loose overlocking stitch or a jamming up problem. The fix is to gently push a pin between the discs, they will move apart quite easily. Now re-thread as needed.... making sure the thread passes in-between the tension discs this time.
19% of the other overlocking issues relate to a thread or fabric jam of some kind. May be the fabric was too thick, the user is pulling fabric through or the machine was not threaded correctly as mentioned above. If this happens whilst using your overlocker, the first fix would be to replace the needles with new ones and of the correct type of course. Secondly, have a close look at the loopers, they do snap and often one may become bent. You will probably not be able to see if a looper has bent unless it's bent double. To check this, rotate the hand wheel gently in the correct direction, making sure loopers are not bashing in too each other or the needles. If there is any kind of contact, the timing may have been knocked out. This would be a task for our sewing machine engineers to correct if needed.
Thirdly, go back to step one, and re-thread correctly!