A Bit of Maintenance for a Shuttle

Recently I had a frustrating day with the tension on my Singer 128K, and the only way I could tighten the bobbin tension was to fish the shuttle out of another machine and use it instead of the shuttle from the 128K.

This is the offending shuttle.  I have finally had a look at it.  First I unscrewed the tension spring and removed it.  Here is the shuttle with the tension spring removed, and you can see that there is a bit of residual muck which had been hiding underneath.  This took only a minute to remove with metal polish.

Here is the underneath of the tension spring, which also needed cleaning up.

On the right hand side there is a tiny groove visible, which is where the thread passes.  The bobbin tension had been too loose.  Even with the screw fully tightened, the tension spring was not holding the thread firmly enough against the shuttle.  

The solution was simple.  All I had to do was exert a little pressure with my fingers on that part of the tension spring to encourage it to lie closer to the shuttle: had I used too much force I would have risked breaking the metal at its thinnest points, so I hesitate to say I bent it.  The change in shape is imperceptible on mere inspection.  Once the shuttle was reassembled and I tried out the stitch, all I needed to do was make a tiny adjustment to the top tension and the stitch was fine.  

Job done.  Now the 128K has its own shuttle back in use. 

Tension Discs with Thumb Tabs

If your machine has a thumb tab beneath the tensions discs, make sure you press the thumb tab when you lift the foot to remove your work after sewing.  This releases the tension on the top thread, so you can pull the thread freely without putting strain on the needle.  This photograph is of the Singer 28K that featured in the machine cleaning video.

Later models have no thumb tab because they were manufactured with a mechanism that automatically released the tension in the top thread when the foot was raised.  It took me a long time to get used to the more modern models after years of sewing only on model 28Ks - every time I lifted the foot my right thumb instinctively pressed a non-existent tab.

How to Adjust the Tension on a Long Bobbin Machine

If a machine has been well looked after, the tension should only ever need adjusting on the top thread.  However, when buying an old machine you never know what tinkering has gone on in the past, and there might be a problem with the bobbin tension.  Adjusting the tension is very difficult to explain without showing the shuttle dangle trick, which I show on this video.

Once you are used to adjusting the tension discs, then regulating the tension on the top thread is a very simple job.  I have been able to remove tension discs for cleaning, replace them and have them set for the correct tension first time, with no further adjustment required and perfect tension when doing the first test stitching.   

However my most beautiful machine (a Vesta transverse Shuttle) was a complete primadonna and it took me four evenings working to past midnight to get it right.  That's when I found out about the shuttle dangle trick.  I hope I have saved people time and headaches by passing on this nugget of sewing machine knowledge.