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How to thread a sewing machine.

A step by step guide to setting up a sewing machine including adjusting tension and troubleshooting.

With pictures! (Because rushing to pause videos at the right bit is a pain in the arse)

Firstly, don’t be afraid of trial and error. Most machines work in a similar way but with slight differences, but if you understand the general set up, you should be able to thread any machine that comes your way. We have mainly Singer Machines and the ones we have taken pictures of are Semi Industrial, models 66K and a 328K (I’ve also included a photo of our industrial Brother zig Zag to give you an idea of how they vary)

1. Choose the right needle and thread.


If you have the wrong needle for your machine brand, the bottom hook may struggle to collect thread in order to send it back up. Provided you have brand compatible needles you will notice they come with names like ‘Leather’ ‘Jersey’ ‘Stretch’ which is kind of self explanatory. If in doubt, just buy ‘Universal’.

As a general rule the lighter the fabric, the smaller needle you’ll need. The two numbers on the needle size are basically just the same thing, one is European and one is American.

What will you be sewing?

Leather/ jeans/ heavier fabric: a Sharps needle has a cutting point so it cuts the fabric, so good for layers of fabrics or big tough ones. Size: 100/16, 110/18 or 90/14

Knit/ lighter fabric: Ballpoint or Jersey needles, rounded tip doesn’t cut into the fabric, but instead pushes aside, so you don’t end up ruining your fabric with massive holes or runs. Size: 90/14, 80/12 or 75/11(60/8 and 70/10 for things like silk and lace)

Stretchy fabric, Lycra, elastic: a Stretch needle, has a ball point but with a ‘scarf’ which kind of allows more room for the bottom hook to grab the thread and stops missed stitches. Size: this depends on how heavy the fabric is, so see above.


For threads, you want to look at thickness and what it is made from. As with needles, the heavier the fabric, the thicker thread you will need, but also more visible the stitch will be.

They are usually measured in ‘tex’ which is basically weight per 1000 metres. Higher the heavier. Obviously.

Light weight fabrics: sizes 16-30

Medium weight fabrics: 30-60

Heavy weight fabrics: 60-135

However, it seems like different brands have different ways of measuring which is really handy. It is a confusing mine field buying thread sometimes as it also can be measured in ‘wt’, which REALLY ANNOYINGLY is where the lower the number, the stronger the thread. So watch out for that.

You can use cotton or polyester/nylon. Polyester threads tend to be stronger, good for thicker fabrics and are good for stretchy fabrics as there is a degree of stretch in the thread. Cottons are suitable for stitching cotton fabric. It is always best to match the thread with the fabric.

2. Threading the machine.

Thread comes in from the right through a retaining loop.

Then straight down into the tension wheel, make sure the thread sits well between the plates.

Clockwise round, on the outside of the little wire moving loop, and up to the arm.

Thread through the hole and then back down again, don’t forget the clip on the left side which directs the thread to the needle.

There is usually a smaller loop on the place that holds the needle to loop through as well.

This is an older machine, and a bit simpler.

Same concept through, in from the right, through a hook.

Down in between tension plates, clockwise round, this time thread goes under wire loop.

Through hook and back up to arm, through hole on arm and down again.

Thread goes through clip on the left side to guide thread towards needle.

This is our industrial machine with a different set up.

Still goes through tension plates and the arm is under the cover on the left, the thread goes around that.

If you have a more modern machine, they have really helpful arrows. The jist is Left – Down – Tension – Up – Down to needle with different variations on the way. The sewing machine often has a model number printed somewhere and it is relatively easy to download instruction manuals for your specific machine if you struggle.

Not done yet.

You need to thread the bottom spool. Spool sits in with thread pulling from the left on this one. Pull end through notch on the right, behind the tension plate and back in through notch on left. Leave a long tail for needle to pull through before you start sewing.

3. Where does the needle go? Which way?

The needles are held in with a tiny screw, which you can undo with a small flat head screwdriver.

This is the front of the needle. Curved top, with a vertical groove (‘scarf’) where the hole is. This faces towards you. Sometimes machines have needle facing outwards, in this case, this side will be facing out left.

This is the back of the needle. The top is flat and there is a horizonatal scoop above the hole. You can figure out which way the needle goes in the machine by looking where the flat bit sits. Push the needle up into the head until you feel resistance. Make sure you tighten the screw well so it won’t work loose.

4. Tension correct and Troubleshooting.

On the top of the fabric:

  1. Top tension slightly too high
  2. Just right, the threads on both sides are pulled evenly.
  3. Just right, the threads on both sides are pulled evenly.
  4. Bottom tension too loose. Top tension too high.
  5. Bottom tension too loose. Top tension too high.

On the bottom of the fabric:

  1. Top tension slightly too loose.
  2. Just right
  3. Just right
  4. Top tension too loose. Bottom too high.
  5. Top tension too loose. Bottom too high.

What does it even mean?

You have two ways of adjusting the tension on your sewing machine. Begin by adjusting the top one first.

Righty Tighty. Lefty Loosey.

Make sure the foot is up before turning. When the foot is down, the plates close together and grip the thread.

Clockwise: tighter = higher tension

Anti Clockwise: looser =lower tension.

Once you adjust, re thread and do a tester piece of fabric before continuing sewing. You can continue to make amendments until it is just right.

Same thing on this simpler one – turn right to make tension high, and left to loosen it.

Bottom spool tension adjustment.

If adjusting the top one doesn’t work, it is worth seeing if it is the bottom one causing all the problems.

The small screws at the bottom of the spool casing. They are the ones you need. There is one screw holding it all together (right one in picture) and the adjustment screw is on the left (the one with the dome head).

Small screwdriver needed – and same thing again: right = tight / left= loose. But only turn it in quarter turns at a time.

There you have it. One sewing machine with thread all in the right places and correct tension throughout.

All sewing machines work on the same principle; a needle pushes a loop of thread through fabric – and a rotating hook goes through the loop and pulls the loop over the thread coming off the bottom spool. When the needle retracts (providing tension is all right) both top and bottom threads are intertwined with the twist hidden inside the fabric at the puncture point.

Don’t be afraid to get stuck in, and learn about how it all works…it will be easier to fix that way.