When I was at school, for the short time I was allowed into the sewing machine room, the whole class was warned never (NEVER) to touch the tension dial. We were all terrified of that tension dial and what could possibly happen if we altered it.
Actually, when something is understood, it is easier to fix and tension isn’t hard to understand and doesn’t need to be a mystery or something to be concerned about. The best way I have found to explain tension is by thinking about a tug of war match. In a sewing machine, you have two teams – one on the top, the top team and one in the bobbin, the bobbin team. Now think about those two teams taking up the tension on the rope, the flag in the middle of the rope sits perfectly on the line between the two teams. How this translates to your sewing machine, is that the meeting of the two threads (from the top and from the bobbin) happens perfectly within the thickness of the material sewn – so the bobbin thread is only seen underneath your work and never on top and the top thread is only seen on the top of your work and not on the underside.
So, by understanding this, we can now look at what ‘bad tension’ refers to. It means that the two teams aren’t pulling with the same strength, they are not balanced. There are two outcomes from unbalanced pulling, or tension.
- When the top team pull too hard, or the bobbin team slacken off, then the flag moves towards the top team. On our sewing machine, this means that the bobbin thread is seen on the top. So, if you see your bobbin thread on the top of your work, it is either because your top tension is too tight, or your bobbin tension is too loose.
- When the top team slacken off, or the bobbin team pull too hard, then the flag moves towards the bobbin team. On our sewing machine, this means that the top thread is seen on the underside of the fabric. So if your top thread is visible on the underside of your work, it is either because your top thread is too loose, or your bobbin tension is too tight.
This concept is a really easy way to decide what is wrong with your sewing if tension is the issue. It will help you decide which changes to make to correct the balance of tension and get your sewing back to perfection. However, before you change any dials, always check these three things first
- Is the machine threaded correctly? In every case unthread your machine (completely) and rethread it.
- Have you got the same type and thickness of thread in the top and in the bobbin? They dont have to be the same colour, but they should be the same type. Some sewing machines are more forgiving of this than others.
- Is your stitch length appropriate for the thickness of the fabric bulk you are sewing – for example, two pieces of quilting cotton would normally have a stitch length of between 1.8-2.2, but sewing up curtain fabric will generally require a stitch length of around 2.8-3.2.
So now you are ready to conquer the world! Go forth – touching that dial should never worry you again!