18 March 2020

Seven Steps to Perfect Thread Tension (with video!)

Seven steps to perfect thread tension - Tilly and the Buttons

Thread tension giving you neck tension? Ever thrown a wobbly because of wobbled stitches?

When the thread tension is off on your sewing machine, it can really throw you. Stitches that are too tight, too loose, or uneven can be particularly disheartening for sewing newbies who aren’t yet comfortable with their sewing machine – but, let’s be honest, thread tension troubles can plague more experienced stitchers too. In fact, it’s surprisingly often that I hear someone saying the reason they don’t sew is that they can’t get the tension right on their machine.

Needle thread tension
Bobbin thread tension

What you’re aiming for is stitches that look evenly balanced on both sides of the fabric, with no loose loops, tight knots or thread bunching.

If the tension is too tight, the fabric can pucker and the bobbin thread may be visible on the top side of the fabric.

If the tension is too loose, you may see visible loops on the top side of the fabric and the spool thread might be visible on the underside.

The good news is that, more often than not, it’s a very simple fix to get your stitching back on track. And very often it doesn’t even involve adjusting the tension dials! So before you spend this month’s fabric budget on getting your machine serviced, work your way through the following steps, in the following order. And some of these steps may surprise you…

Plus there's a video at the end if you'd like to see these steps in action!

Spool unravelling on sewing machine

1) Check the spool is the right way up

The simplest solution is often the best one. It may sound obvious but, when I teach sewing classes and anyone is having thread issues, nine times out of ten the culprit is the spool thread being on upside down.

The spool thread is the one that goes on top of your machine. If it sits horizontally on your machine, check that the thread is unwinding over the top of the spool towards the back of the machine. Or, if you have a machine on which the spool sits upright, check it’s unravelling in an anticlockwise direction, from the back of the spool rather than the front. (This is how to thread the vast majority of sewing machines, but do check your manual in case yours is different!)

Removing stickers on thread spool

2) Remove any spool stickers

I know, I know, this sounds ridiculous. But I can’t be the only one to have fallen foul of those little labels that sit either end of a spool of thread… can I?! If they’re sticking the spool to the spool pin, it’s not going to unravel smoothly. So take the two seconds needed to remove them completely before you start sewing, and you can thank me later :)

Thread threaded through hooks

3) Check all guides are threaded

Your sewing machine will have various hooks and levers on it, the purpose of which is to hold the spool thread at the correct level of tautness. So, if the spool has come loose from one of them – or you’ve simply forgotten to thread it through all of them – the tension on the upper stitches could end up too loose.

The number and position of thread guides varies from machine to machine, so this is one of those things to check on your manual. One hook that is often overlooked is the little one that sits just above the needle – don’t forget to thread that one too!

And make sure your presser foot is raised as you’re threading the spool. One thing you may not realise is that the presser foot engages the tension discs so, if it’s down while threading, the thread may not get properly into position.

Thread caught on bobbin winder guide

4) Check the spool thread isn’t caught on the bobbin winder guide

One thing the spool thread should not be caught on is the bobbin winder thread guide. This little nubbin on top of your machine is used for winding the bobbin thread only. An easy mistake to make is to forget to take the spool thread off it once you’ve finished winding your bobbin. If you leave it on, it will create super tight tension – so do check!

Inserting bobbin correct way

5) Check the bobbin is inserted correctly

Again, the simplest solution is often the best one, so make sure your bobbin is loaded properly.

On top-loading machines, where the bobbin case lies horizontally, the thread should be unwinding in an anticlockwise direction as you’re looking at it from above. On a front-loading machine, where the bobbin case stands up vertically, the thread usually unwinds in a clockwise direction. Again, do check your manual in case it’s different on your machine.

And, while you’re here, check the thread is caught on the hook or channel inside the bobbin case. If it comes free, it can make for stitches that are loose on the underside of the fabric.

Adjusting thread tension dial on sewing machine

6) Adjust the spool tension dial

Chances are it’s one of the five things listed above that’s causing the thread tension issue. But, if they were all done correctly, and if your tension is still not right, the next thing to try is adjusting the tension of the spool thread.

Check the default setting for your tension dial in your sewing machine manual. On machines I’ve used, it’s usually 4. Set it to this and sew a test line of stitching on a double scrap of the fabric you’re using for your current or next project.

Needle thread tension
Bobbin thread tension

If the stitches on the top layer of the fabric look too tight, if you can see the bobbin thread on the top layer of fabric, and/or if the fabric is puckered, try lowering the needle thread tension by turning the tension dial to a lower number.

If the stitches on the top side look like loose loops and the needle thread is visible on the underside of the fabric, dial up the tension setting to a higher number.

It’s best to make these adjustments in small increments – increase or decrease it by one number at a time, sewing a test line of stitches each time until they look balanced on both sides.

Thread tension will vary with different fabrics. As a general rule, I’d lower the tension for thicker fabrics such as sweatshirt fleece to allow the stitches more give to get over the material, and tighten the tension for lighter weight fabrics such as a single crepe or silky lining. Also, if you’re using a thicker thread, such as a topstitch thread, you may well need to turn the dial down to allow the thread to pass through the tension discs.

Screws to adjust bobbin case tension

7) Adjust the bobbin case tension

If you’ve worked your way through the steps above and the tension is still off, the last thing I’d do before booking a professional service is to adjust the bobbin case tension.

The reason I’d leave this step until last is that it’s possible to get into a bit of a pickle here if you don’t take note of what the default bobbin tension setting is. While the spool tension is controlled by an easy-to-adjust, numbered tension dial, the bobbin tension is changed by turning a teeny tiny, unlabelled screw on the side of the bobbin case. So, before you begin, take a quick photo of the angle the groove of the screw is sitting in, so you can reset it later if you need to.

Grab a small screwdriver and turn the screw slightly – clockwise to tighten it if the stitches on the underside of the fabric look loose and loopy, anticlockwise to loosen it if they look too tight (righty-tighty, lefty-loosey!).

As before, change it little by little – about 90 degrees each time – checking the tension on a test swatch each time, until the stitches look balanced on both sides.

Want to watch these tips in action? We've made you a video...

I hope this has saved you some head-scratching and given you more confidence in fixing tension troubles. If you’ve worked your way through these steps and still can’t solve the issue, it may be time to take your machine in for a professional service. Yes, it’s not cheap – but worth it to get your sewing back on track :)

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Author: Tilly Walnes
Photos: Jane Looker